A
- a escape sequence, 174
- aa-complain command, 115
- aa-disable command, 119
- aa-unconfined command, 113
- AAA (Authentication, Authorization, Accounting) services, 116
- --abort option for merge conflicts, 176
- access control lists
- accounts
- acl command, 73
- active-backup mode for network bonding, 30
- active/passive mode for network bonding, 30
- addresses. See IP addresses
- age limits for passwords, 121
- agent orchestration, 164, 198
- agentless orchestration, 183
- alerts, escape sequences for, 174
- aliased commands, 178
- aliases for email, 66
- allow-guest=false option, 135
- AllowUsers directive, 108
- alsamixer command, 82
- anaconda and kickstart, 31
- Ansible package, 162
- Apache servers
- configuration file, 77
- restarting, 75
- SSL private keys, 83
- AppArmor
- appending output
- to files, 167
- to STDOUT, 78
- apt-cache search command, 51, 188
- apt-get update command, 52, 130
- apt-get upgrade command, 48, 129
- archive mode for rsync command, 71
- arguments, number of, 177
- arp command, 144–145
- arrays
- at now command, 62
- atq command, 189
- atrm command, 63
- attributes for files, 154, 156
- audio, mixer volumes, 82
- auditd daemon, 117
- ausearch command, 152
- authentication
- biometric, 114
- Kerberos, 104, 112, 121
- keys, 190, 194
- LDAP, 122, 154
- logs, 115
- mechanisms, 194
- network components, 117
- PAM, 122
- rndc, 103
- server UIDs and GIDs, 64
- Authentication, Authorization, Accounting (AAA) services, 116
- authoritative name servers, querying, 16
- authorization
- authorized_keys file, 98
- autofs automounter, 70
- automatic logouts, 177
- automation
- build, 168, 180
- configuration management, 166
- infrastructure, 165, 178
- inventory attributes, 174
- automount options, 70
- AVC messages, 155
- awk command, 195
B
- background tasks, viewing, 133
- backquotes (`) for commands, 168
- backslashes () for escape characters, 163
- backups
- extracting files from, 117
- incremental, 114
- patch command, 198
- backward searches with less command, 58
- bad blocks
- checking for, 147
- displaying, 23
- balance-rr mode for bonding scenarios, 35
- bare-metal hypervisors, 34
- baseurl option for package repositories, 72
- .bash_history file, 195
- .bash_profile file, 60
- Bash shell, invoking, 163
- bcfg command, 22
- bell, escape sequences for, 174
- /bin/false shell, 135
- BIND
- chroot scenario, 103
- reloading, 77
- server configuration, 73
- server control, 79
- biometric authentication, 114
- BIOS
- passwords, 114
- SATA disks, 194
- blacklist information for modules, 21
- blkid command
- blob storage, 31
- block devices, information on, 142
- blocks
- Bluetooth devices, detecting, 85
- bonded-link aggregation, 33
- bonding scenarios, load balancing in, 35
- /boot/efi partition,
- /boot/grub/grub.conf file, 110
- /boot partition
- boot times for services, 76
- booting
- changing order, 22
- configuration, 22
- device checking order, 12
- from HTTP and FTP, 28
- kernel ring buffer,
- kickstart, 35
- location, 27
- lsblk command, 72
- preventing, 114
- single-user mode,
- troubleshooting, 129
- bootloaders
- brace expansion in echo command, 164
- brctl command, 36
- bridging vs. NAT, 30
- btrfs filesystems, 11
- buffers column for memory usage, 150
- build automation, 168, 180
- build files, excluding, 176
- bypassing
- locale translations, 14, 179
- routing tables, 198
- byte-to-inode ratio, 149
- bzImage, creating, 191
- bzip2 command, 103
C
- caches
- Kerberos authentication, 112
- package, 52
- purging, 33
- shared libraries, 48, 129
- Cacti tool, 143
- caja file manager, 76
- carriage returns, escape characters for, 198
- case statements
- clause ends, 178
- default case, 169
- terminating, 173
- cat /etc/passwd command
- contents output, 55
- description, 179
- usernames, 54
- cat /proc/interrupts command, 46, 186
- CentOS 7 bug-reporting tool, 78
- certificate authority servers, 73
- Certificate Signing Requests (CSRs), 77
- certificates in Postfix TLS, 105
- cfq scheduler, 150
- chage command
- chaining commands, 169, 174
- change date for passwords, 64, 69
- character case, converting, 83
- characters
- attributes, 189
- multibyte representation, 13
- supported character sets, 32
- chattr command, 154
- chcon command, 113
- checksums for files, 118
- chgrp command
- group ownership, 94–95
- web servers, 59
- chkconfig —level command, 79
- chkconfig —list command, 47
- chmod command
- permissions, 111
- privileges, 95
- recursive changes, 95, 169
- script execution, 162
- sticky bits, 95
- chown command, 118, 152
- chroot scenario with BIND, 103
- CIFS (Common Internet File System), 32
- clock
- setting, 15
- UTC time, 15
- working with, 14
- cloning repositories, 165, 177, 195
- cloud-init command, 32
- cluster servers, 79
- collection of devices, 163
- command execution
- customized environments, 162
- on logout, 171
- in non-interactive sessions, 99
- source commands, 171
- subshells, 166
- command-line interface for Network Manager, 150
- commands
- aliased, 178
- arguments, 177
- backquotes, 168
- chaining, 169, 174
- executed on logout, 171
- exiting shell, 172
- from files, 171
- history, 171, 195
- kernel modules, 30
- location, 171
- multiple, 167, 182
- parameters, 172
- paths, 176
- scheduling, 62
- SQL, 168
- time to execute, 31
- user input, 172
- comments
- /etc/inetd.conf file, 100
- scripts, 164
- commits
- automatic, 180
- history, 168, 174
- Common Internet File System (CIFS), 32
- comparing
- complain mode for AppArmor profiles, 115
- completed print jobs in CUPS, 67
- compression
- .gz files, 72
- logs, 97
- lzma files, 94
- tar command, 102
- configuration management automation, 166
- connection points for USB disks, 129
- connections
- hypervisors, 32
- SSH, 197
- troubleshooting, 140
- USB devices, 48
- X severs, 135
- console logins by root user, 111
- containers, 75
- contexts
- converting character case, 83
- copying
- cp command
- directories, 55
- overwriting files, 55
- cpio utility, 117
- cron
- directory, 63
- entry lists, 65
- job execution, 62
- scheduled tasks, 96
- system-wide files, 63
- users, 62
- crontab command
- entry lists, 65
- removing jobs, 196
- cryptsetup command, 101
- CSRs (Certificate Signing Requests), 77
- Ctrl+Alt+Del keys, disabling, 110
- Ctrl+C keys
- terminating daemons, 77
- terminating scripts, 175
- Ctrl+Z keys for suspending daemons, 83
- CUPS system
- completed print jobs, 67
- configuration, 66
- default ports, 67, 152
- restarting, 68
- curl command, 80
- currency-related localization, 14, 181
- current default route, 199
- currently mounted filesystems, 10
- custom commands for kernel modules, 30
- custom logs, 67
- customized environments, command execution in, 162
- cut command, 55
- CVE process for security bulletins, 116
D
- daemons
- configuration files, 81
- local servers, 149
- stopping, 81
- suspending, 83
- terminating, 77
- datagram security, 112
- Datagram Transport Layer Security (DTLS), 112
- date command, 15
- dates
- dd command
- megabyte IO, 193
- partition images, 94, 118
- Debian systems, updating, 48, 129
- debugfs command, 188
- debugging, enabling, 27
- debugging logs for libvirt, 31
- declare command, 173, 175
- declaring variables, 166
- default base port in VNC, 78
- default branches in repositories, 169
- default configuration for BIND servers, 73
- default delimiters, 55
- default gateways
- default paths, 176
- default ports
- default route, displaying, 15, 199
- default.target unit, 191
- default targets, displaying, 47
- defaults line in/etc/fstab file, 24, 192
- delimiters, setting, 81
- deny policy for access control lists, 149
- dependencies
- displaying, 21, 51, 186–187
- libraries, 48, 130
- loaded modules, 20
- loading,
- depmod command
- dependencies, 20
- module comparisons, 35
- detected hardware list, 157
- /dev/disk/by-id directory, 24
- /dev/disk/by-multipath directory, 35
- /dev/disk/by-path directory, 25
- /dev/disk/by-uuid directory, 33
- /dev filesystem, 32
- /dev/mapper directory, 26, 71
- /dev/null directory, 81
- /dev/nvme* directory, 70
- /dev/pty device, 115
- /dev/sda1 partition, , 94
- /dev/sdX device, 50, 128
- /dev/tty device, 84
- devices
- boot checking order, 12
- collection of, 163
- displaying names of, 50, 187
- information on, 74
- lsmod driver display,
- pseudo-terminals, 115
- df command
- disk utilization, 19, 190
- inodes, 134
- report scale, 147
- DHCP
- configuration, 36
- leases, 194
- server system log, 71
- dhcpd.conf file, 194
- diff command, 77
- dig command
- mail server queries, 16, 137
- server queries, 17
- Start of Authority information, 18, 139
- zone transfers, 19, 140, 193
- digital signatures, 119
- directories
- copying, 55
- creating, 55
- finding, 54
- large files on, 10, 134
- listing, 167
- log configuration, 121
- permissions, 153
- profiles, 112
- removing, 54
- traversal, 118
- UFW configuration, 120
- disabling
- accounts, 196
- Ctrl+Alt+Del keys, 110
- hostname lookups, 148
- logging, 35
- disks
- detecting, 128
- GRUB Legacy configuration file,
- preparing,
- RAM, 20–21, 191
- SATA, 50, 128, 194
- space usage, 136
- statistics, 146
- unallocated space, 30
- USB, , 129
- utilization display, 19, 190
- DISPLAY environment variable, 60
- display port setting, 75
- DisplayBase option, 75
- dm-crypt
- encryption, 197
- volume configuration, 101
- dmesg command
- kernel ring buffer, , 71, 186
- logs, 35
- RAID adapters, 153
- USB disks, 129
- video cards, 83
- dmidecode command, 155
- dnf search command, 53
- DNS
- overriding, 18
- server setting, 17, 137
- SPF records, 19, 140
- troubleshooting, 140
- dnssec-keygen command, 103
- do keyword
- for loops, 175
- until loops, 180
- dollar signs ($)
- command execution, 166
- command-line arguments, 177
- domains, information on, 13
- dominfo command, 13
- done keyword
- for loops, 175
- until loops, 180
- dot (.) files, displaying, 117
- dpkg command
- package changes, 52
- package information, 53, 132
- dracut command, 21
- drivers
- displaying, 36
- network interfaces, 36
- DROP targets for iptables, 106
- DTLS (Datagram Transport Layer Security), 112
- du command
- human-friendly format, 34
- large files on directories, 10, 134
- summary output, 157
- dual-homed networks, 29
- dumpe2fs command, 12, 23
E
- -e option for file existence, 178
- e2label command, 29
- EC2 instances, 32
- echo command
- brace expansion, 164
- forwarding, 107
- newline characters, 169
- paths, 166
- variable display, 162
- ECHO_REQUEST packets, 193
- echo requests in ICMP, 147
- echoing script names, 165
- editing
- /etc/sudoers file, 100
- files, 114
- EFI system partition,
- efibootmgr command, 22
- egrep command for finding users, 56
- elif keyword, 181
- email
- address changes, 170
- aliases, 66
- destinations, 26, 108
- statistics, 68
- emailing logs, 97
- emergency target, 197
- empty passwords, 106
- encrypted devices, listing, 23
- encryption
- authentication passwords, 156
- dm-crypt command, 197
- group passwords, 65
- Enforcing mode in SELinux, 110
- enumerating hosts database, 17, 137
- env command
- customized environments, 162
- displaying, 132
- environment variables, 167, 171
- Environment key, 81
- environment, printing, 165
- environment variables
- -eq operator for integer comparisons, 174
- equal signs (=)
- string comparisons, 165
- variable comparisons, 176
- error corrections
- automatic, 134
- swap partition, 134
- error fixes with fsck command, , 191
- esac sequence, 173
- escape sequences
- alerts, 174
- carriage return and newline, 198
- quotes, 163
- /etc/apparmor.d directory, 112
- /etc/apparmor.d/tunables directory, 119
- /etc/apt/sources.list file, 52, 131
- /etc/auto.master file, 70
- /etc/bash.bash_logout file, 171
- /etc/cron.allow file, 62
- /etc/cron.daily directory, 63
- /etc/cron.deny file, 96
- /etc/crontab file, 63
- /etc/crypttab file, 23
- /etc/cups directory, 66
- /etc/default/grub file
- changes to,
- timeouts,
- /etc/default/keyboard file, 152
- /etc/dhcpd.conf file, 36
- /etc/exports file, 194
- /etc/fail2ban directory, 106
- /etc/fstab file
- defaults line, 24, 192
- device checking order, 12
- filesystem information, 10
- format, 11
- mount command,
- /etc/grub2.cfg, 28
- /etc/gshadow file, 65
- /etc/hosts.allow file, 101
- /etc/hosts.deny file, 99
- /etc/hosts file
- correct line in, 17, 138
- hostnames, 27
- localhost addresses, 16
- /etc/inetd.conf file, 100
- /etc/init.d directory
- linked files, 70
- scripts, 46
- /etc/inittab file
- changes to, 49
- Ctrl+Alt+Del keys, 110
- runlevels, 70, 190
- /etc/issue file, 102
- /etc/issue.net file, 102
- /etc/lib file, 130
- /etc/localtime file, 189
- /etc/logrotate.conf files, 97
- /etc/logrotate.d directory, 121
- /etc/mdadm.conf file, 26
- /etc/modprobe.conf file, 30
- /etc/modprobe.d directory, 21
- /etc/motd file, 102
- /etc/mtab file, 10
- /etc/netplan directory, 34
- /etc/network directory, 27
- /etc/nologin file
- login prevention, 141
- PAM for, 104
- /etc/nsswitch.conf file
- authentication, 194
- group information lookups, 16
- /etc/pam.d directory, 104
- /etc/passwd file
- home directories, 103
- output location, 55
- user information, 61
- usernames, 54
- /etc/pki directory, 108
- /etc/profile.d directory, 80
- /etc/rc.d directory, 70
- /etc/rc.local file, 79
- /etc/rcS.d directory, 80
- /etc/resolv.conf file
- debugging setting, 27
- DNS servers, 17, 137
- local client services, 18, 139
- /etc/rsyslog.conf file, 120
- /etc/securetty file, 111
- /etc/security/limits.conf file
- process limits, 141
- simultaneous logins, 142
- /etc/services file, 98
- /etc/shadow file
- encrypted passwords, 156
- password change dates, 69
- passwords, usernames, and UUIDs in, 64
- /etc/skel directory, 60, 189
- /etc/ssh_known_hosts file, 100
- /etc/sshd/sshd.conf file, 100
- /etc/sudoers file
- editing, 100
- email destinations, 108
- passwords, 99
- /etc/sysconfig/network file, 33
- /etc/sysconfig/network-scripts/ directory, 29
- /etc/sysctl.conf file, 21
- /etc/timezone file, 13
- /etc/udev directory, 46, 186
- /etc/ufw directory, 120
- /etc/X11 directory, 82
- /etc/X11/xorg.conf file, 60
- /etc/yum.conf.d directory, 51, 130
- /etc/yum.conf file, 52, 131
- /etc/yum.repos.d directory, 72
- ethernet bridges, creating, 36
- ethtool command, 36
- events, replaying, 78
- exclude patterns in git command, 199
- ExecStart option, 47
- executable files
- location, 58
- permissions, 95
- execute bit for scripts, 199
- execution
- commands. See command execution
- scripts, 162, 164
- of services on boot, 79
- existence of files, 135, 178, 198
- existing files with touch command, 55
- exit codes
- general errors, 180
- success, 164
- expansion of variables, 183
- expiration of accounts, 69, 96, 190
- export command
- environment variables, 195
- libraries, 130
- variables, 166, 195
- ext2 filesystems,
- ext3 filesystems
- vs. ext2 filesystems,
- resizing, 31
- extended hardware information, information on, 155
- extensions
- determining, 170
- script execution, 164
- extracting files from backups, 117
F
- fail option for RAID arrays, 156
- fail2ban system
- configuration, 106
- log file locations, 107
- failed login attempts
- account locking, 115
- listing, 112
- FAT filesystem for cluster servers, 79
- fdisk command,
- fg command, 56
- FHS (Filesystem Hierarchy Standard)
- mount points for removable media, 10
- site-specific data,
- fi keyword, 169
- FibreChannel HBA, 149
- file command, 170
- file extensions
- determining, 170
- script execution, 164
- files
- access control lists, 111
- appending output to, 167
- attributes, 154, 156
- backups, 198
- checksums, 118
- commands from, 171
- committing, 180
- comparing, 77
- contents, 72
- contexts, 120
- copying, 60, 85, 117, 189
- creating, 135
- editing, 114
- existence, 135, 178, 198
- inode index numbers, 58–59
- linked, 70
- listing, 54, 167
- matching, 177
- modifying, 103
- moving, 57
- output to,
- overwriting, 55
- owned by users, 66
- ownership, 112, 118, 152
- permissions, 112
- print queues, 67
- relative paths, 30
- removing, 84, 102
- searches, 141–142
- size, 154, 193
- symlinks, 58
- transferring, 116
- uncompressing, 72, 94, 102
- Filesystem Hierarchy Standard (FHS)
- mount points for removable media, 10
- site-specific data,
- filesystems
- checking, 12
- cluster servers, 79
- information on, 10
- labels, 29
- remounting, 11
- shared by NFS, 194
- size, 31
- times mounted, 10–11
- type setting, 23
- unmounting, 73
- unreachable, 27
- verification, 24
- find command
- directories, 54
- files, 141–142
- files owned by users, 66
- inode numbers, 59
- modified files, 57
- users invoking sudo command, 57
- finding zombie processes, 157
- firewall-cmd command, 116
- firewalld, zones for, 110
- firewalls
- for loops
- foreground, bringing commands to, 56
- formats for dates and times, 13, 175
- formatting printing, 84
- forwarding, enabling, 107
- fprint package, 114
- free command for memory usage, 133, 150, 190
- fsck command
- cleaned filesystems, 143
- disk statistics, 146
- error fixes, , 191
- filesystem checking, 12
- inodes, 134
- root check skipping, 33
- fstrim command, 25, 192
- FTP, booting from, 28
- functions
- adding, 163
- available at login, 60
- example, 196
- parentheses for, 173
G
- G flag for route tables, 140
- gateways, default
- gdisk command
- GUID partition tables, 111
- partition names, 12
- general errors, exit codes for, 180
- getenforce command, 109
- getent command
- getfacl command, 111
- getsebool command, 113
- GIDs and UIDs, 64
- git checkout command, 166, 182
- git clone command, 195
- git commit command, 180
- git config command
- configuration parameters, 179
- email addresses, 170
- GIT_DIR environment variable, 176
- .git directory for repository metadata, 182
- git log command, 168, 174
- git ls-files command, 199
- git merge command, 176
- git pull command
- positional parameters, 180
- shared repositories, 180
- git push command, 168
- git remote show origin command, 177
- git status command, 169
- .gitignore file, 167
- GnuPG key pairs, 100
- gpg command
- digital signatures, 119
- key pairs, 100
- public keyrings, 101
- GPIO interface, 76
- graphics cards configuration information, 60
- grep command
- file contents, 72
- system log, 71
- groupadd command, 80
- groupdel command, 65
- groupmod command, 62
- groups
- adding, 80
- encrypted password information, 65
- IP addresses, 150
- lookup information, 16
- membership lists, 155
- names, 62
- ownership, 94–95
- printers, 68
- removing, 65
- su command access, 113
- for users, 64
- grub-install command
- alternate directories, 23
- MBR,
- GRUB installed on MBR, –8
- GRUB Legacy configuration file,
- GRUB menu, , 186
- grub-mkconfig command,
- GRUB2 configuration files
- grub2-install command,
- grub2-mkconfig command
- booting location, 27
- output to files,
- grubx64.efi file, 23
- guest logins, preventing, 135
- GUID partition tables, information on, 111
- gunzip command, 72
- .gz files, 72
- gzip command, 103
H
- hangup signals for processes, 148
- HAProxy server 400 response, 76
- hard drives
- detecting, 128
- preparing,
- hard links, 58
- hardware
- information on, 155
- listing, 157
- hardware clock
- setting, 15
- UTC time, 15
- working with, 14
- hashing algorithms for PKI, 113
- head command, 54, 56
- HEAD location, 166
- HISTFILESIZE option, 195
- history
- hmac-md5 algorithm, 103
- home directories
- changing, 64
- chroot, 103
- copying files, 60
- creating, 63
- HOME environment variable, 173
- horizontal tabs, 176
- host command
- authoritative name servers, 16
- authorization name servers, 136
- class type, 157
- hostname characters, 27
- hostname lookups
- disabling, 148
- preventing, 153
- hostnamectl set-chassis command, 78
- hosts
- hotplug devices, USB, 47
- HTTP 405 status code with TraceEnable, 85
- http_access directive, 74
- HTTP, booting from, 28
- hwclock command for hardware clock
- setting, 15
- UTC time, 15
- working with, 14
- hypervisors
- connections, 32
- Type 1, 34
I
- ibstat command, 148
- ICMP
- echo requests, 147
- interface for, 16, 136
- iptables rules, 107
- ports, 98
- iconv command, 32
- id command, 65
- id_rsa file, 99
- IDs
- if conditionals
- end character, 169
- file existence, 135
- ifconfig command, 136
- iftop command
- hostname lookups, 153
- interface setting, 156
- network usage, 150
- images for partitions, 94, 118
- IN class for host command, 157
- incremental backups, 114
- inet protocols
- default, 26
- ip command, 144
- InfiniBand devices, information on, 148
- informational messages, 66
- infrastructure as code, 162
- infrastructure automation, 165, 178
- inheriting permissions, 111
- init command, 46
- initialization files, shell execution without, 60
- initializing partitions, , 131
- inode index numbers
- printing, 58
- searching for files by, 59
- inodes
- byte-to-inode ratio, 149
- partitions, 134
- input, user, 172
- INPUT chain policies, 106
- insert mode for Vi editor, 57
- insmod command, 21
- install command, make command targets, 72
- installing
- integers, comparing, 174, 182
- interactive logins, 135
- interactive mode for NTP servers, 67
- interfaces
- displaying, 145
- ICMP packets, 16
- iftop, 156
- information on, 136
- netstat display of, 175
- Raspberry Pi, 76
- interpreter location, 171
- interrupts, monitoring, 147
- inventories
- automated infrastructure, 174
- device collections, 163
- invoking Bash shell, 163
- IO, scheduling, 150, 153
- ioping command
- iostat command
- involuntary wait scenario, 178
- megabyte display, 191
- partition information, 19, 142
- IP addresses
- groups, 150
- NTP servers, 66
- ownership, 151
- private, 136
- ip command
- default protocol, 26
- newlines, 145
- protocol family, 144
- ip monitor command, 16, 137
- ip route change command
- commands following, 19
- default gateways, 18, 138
- ip route flush cache command, 19, 140
- iperf command, 147
- ipset command
- iptables
- ICMP traffic, 107
- INPUT chain, 106
- ipset software, 120
- log entry limits, 106
- Netfilter, 117
- PREROUTING chain, 105
- rules, 105–107
- targets, 106, 108
- UFW configuration, 120
- iptables-save command
- iptraf command, 150
- IPv6 localhost addresses, 16
- IRQ assignments, viewing, 46, 186
- ISOLINUX bootloader, 22
- itop command, 147
- iw dev command, 71
- iwconfig command, 26, 83
J
- JAVA_PATH environment variable, 195
- JavaScript Object Notation (JSON) format, 28
- jobs
- journalctl command
- disk space, 136
- log entries, 96, 121
- log-file entries, 196
- reverse output, 197
- journald.conf file, 97
- journaling in ext3 filesystems,
- JSON (JavaScript Object Notation) format, 28
K
- Kerberos authentication
- KerberosAuthentication option, 121
- kern facility, 96
- kernel
- installing, 30
- message logs, 96
- parameters, 148
- udev events, 70
- updating, 52, 131
- upgrading, 69
- version, 52, 131
- kernel-install command, 30
- kernel modules
- custom commands, 30
- installing, 20
- loaded,
- location, 28
- kernel ring buffer
- clearing, 71
- kernel panic messages, 28
- viewing, , 186
- keyrings in gpg, 101
- keys and key pairs
- Apache servers, 83
- authentication, 190, 194
- certificate authority servers, 73
- GnuPG, 100
- layout, 29
- LUKS, 101
- mapping, 152
- Postfix TLS, 105
- sending, 100
- SSH, 98–99, 107, 118, 120, 194
- ssh-agent, 110
- kickstart
- and anaconda, 31
- booting, 35
- kill command
- BIND reloading, 77
- processes, 56–57, 148
- killall command, 133
- killing processes, 133, 200
- klist command, 112
- kmag command, 61
L
- labels for filesystems, 29
- LACP protocol, 33
- LANG environment variable, 14, 179
- large files on directories, 10, 134
- last command for logs, 68
- lastb command for failed login attempts, 112
- latency
- diagnosing, 151
- ping command, 147
- LC_ALL environment variable, 14, 178
- LC_MONETARY environment variable, 14, 181
- LC_TIME environment variable, 13, 175
- LDAP
- ldconfig command, 48, 129, 200
- ldd command, 48
- leases, DHCP, 194
- legal disclaimer information, suppressing, 156
- less command, 58
- /lib/systemd/system folder, 49
- libraries
- LIBVIRT_DEBUG, 31
- libvirt for debugging logs, 31
- limits
- PAM, 122
- password age, 121
- processes, 141
- simultaneous logins, 142
- users, 99
- lines, printing, 54
- linked files, 70
- links cache wireless device status, 71
- links for shared libraries, 48, 129
- --list option for configuration parameters, 179
- ln command
- symlinks, 58
- time zones, 14
- load average, 133, 142, 200
- load balancing in bonding scenarios, 35
- loaded modules, displaying
- currently loaded, 20
- kernel,
- loading modules and dependencies,
- local authentication for encrypted passwords, 156
- local client services, enabling, 18, 139
- local command for variables, 165
- local servers, daemons on, 149
- local time zones, 13
- local variables, indicating, 165
- local# facilities for custom logs, 67
- locale
- currency, 181
- translations bypassing, 14, 179
- variable reconfiguration, 14, 178
- localectl command, 29
- localhost in IPv6, 16
- locate command for database updates, 59
- locking accounts, 115
- locking out password-based logins, 63
- --log-prefix option for iptables, 108
- logged-in users, 68–69, 142
- logical volumes
- creating, , 131, 192
- directories, 71
- information on, 26
- logical creation order,
- logins
- 3D acceleration, 75
- console, 111
- environment, 101
- interactive, 135
- preventing, 104, 141
- simultaneous, 142
- user information, 73
- logouts
- commands executed on, 171
- processes running after, 85
- users, 177
- logpath option, 107
- logrotate command, 121
- logrotate configuration file, 97
- logs and log files
- authentication and authorization, 115
- compression, 97
- custom, 67
- disabling, 35
- emailing, 97
- entry display, 120–121
- entry limits, 106
- entry parsing, 196
- journals, 97
- kernel messages, 96
- last command, 68
- locations, 107
- output from, 76
- output to, 163
- packets, 122
- systemd-journald service, 96
- watching, 94
- loops
- lpr command
- capturing messages, 196
- print queues, 67
- lpxelinux.0 file, 28
- ls command
- dot files, 54, 117
- example, 50
- filters, 167
- hard links, 58
- inode index numbers, 58
- ownership, 112, 149
- partitions, 128
- permissions, 59, 112
- SELinux, 119
- symbolic links, 186
- lsattr command, 156
- lsblk command
- boot partitions, 72
- partition information, 36
- lsdev command, 74
- lshw command, 157
- lsmod command
- device drivers,
- loaded modules, , 20
- lsof command, 141
- lspci command
- listing, 187
- numeric codes and device names, 50, 187
- lsusb command
- Bluetooth devices, 85
- USB connections, 48
- USB devices, 46, 128
- -lt operator, 181
- LUKS
- encryption, 197
- key-derivation function, 101
- LUNs
- from Fibre Channel, 25
- paths, 25
- lvcreate command, , 131, 192
- LVM
- logical volumes, , 131
- partitions, , 131
- lvmdiskscan command, , 132
- lzma extension, 94
M
- MAC addresses
- new entries, 145
- removing, 144
- machine type setting, 78
- magnification functionality, 61
- mail command for STDIN messages, 73
- mail option for emailing logs, 97
- mail queues
- directories, 66
- Postfix servers, 67
- mail servers
- mail storage, 187
- MAILADDR option, 26
- mailstats command, 68
- mailto option, 108
- make command
- commands and relationships used with, 72
- targets, 72
- make oldconfig command, 69
- Makefile name, 72
- Master Boot Record (MBR)
- GRUB on, –8
- partition information, 22
- primary partitions,
- master branch in repositories, 169
- matching files, 177
- MATE desktop environment, 76
- max-lease-time option, 194
- maximum mount count, 199
- maxlogins option, 142
- MBR (Master Boot Record)
- GRUB on, –8
- partition information, 22
- primary partitions,
- mdadm command
- arrays, 25, 192
- email, 26
- polling interval, 145
- RAID arrays, 26
- /media file, 10
- membership lists for groups, 155
- memory usage
- merge command for repositories, 164
- merge conflicts, rolling back, 176
- messages
- capturing, 196
- informational, 66
- kernel logs, 96
- netlink, 16, 137
- repositories, 168
- for users, 102
- warning, 103
- welcome, 61
- metadata in repositories, 182
- mixer volumes, 82
- mkdir command
- directories, 55
- repositories, 163
- mke2fs command
- bad blocks, 147
- changing, 149
- filesystem type, 23
- mkfs.btrfs command, 11
- mkinitrd command, 20, 191
- mkswap command, 134, 192
- modified files, finding, 57
- modifying files, 103
- modinfo command, 20
- modprobe command,
- dependencies, 21, 186
- kernel module, 20
- removing modules, 21
- modules
- blacklist information, 21
- comparing, 35
- dependencies, 21, 186
- inserting, 21
- loading,
- removing, 21
- unloading, , 35
- monitoring
- interrupt usage, 147
- performance, 69
- processes, 188
- monitors
- more command, 84
- mount command
- /etc/fstab files,
- mount process simulation, 199
- partitions, 22
- USB devices, 12
- USB disks,
- mount count maximum, 199
- mount points for removable media, 10
- mounted filesystems
- displaying, 32
- /etc/mtab file, 10
- moving
- files, 57
- positional parameters, 180
- mtr command, 145
- multibyte representation, 13, 189
- multipath command, 25
- multiple commands, running, 167, 182
- mv command
- overwriting files, 55
- text files, 57
- MX records, 193
- MySQL default ports, 82
N
- nagios software, 69
- NAME option for network adapters, 82
- name resolution
- name servers
- named.conf file, 73
- names
- changing, 65
- groups, 62
- network adapters, 82
- partitions, 12
- nameserver line, 17
- Nano editor, 83
- NAT vs. bridging, 30
- nc command, 139
- net command, 104
- NetBIOS name service requests, 74
- netcat command, 139
- Netfilter firewalls, 117
- netlink messages, 16, 137
- netstat command
- current default route, 15, 199
- hostname lookups, 148
- interface information, 175
- routing tables, 157
- services and sockets, 17, 138
- network adapter names, 82
- network bonding, 30
- network interfaces, drivers, 36
- Network Manager, 150
- networks
- component authentication, 117
- configuration, 29
- configuration saving, 33
- throughput measuring, 147
- usage displaying, 150
- new files, permissions for, 95
- newaliases command, 66
- newlines
- echo command, 169
- escape characters, 198
- removing, 145
- nice command, 133
- nmap command
- name resolution, 145
- open ports, 141–142
- Xmas scans, 146
- nmbd daemon, 74
- nmcli command, 150
- --no-commit option for shared repositories, 180
- nocompress option for logs, 97
- nohup command, 85
- non-interactive mode
- command execution in, 99
- sudo command, 119
- non-swap partitions, 132
- NOPASSWD option, 99
- --norc option for shell execution without initialization files, 60
- nslookup command, 36, 154
- NTP
- interactive mode, 67
- IP addresses, 66
- ports, 108
- ntpq command, 67
- numeric codes, displaying, 50, 187
- NXDOMAIN message, 140
O
- o command in Vi editor, 57
- octal notation for permissions, 120
- open ports, scanning for, 141–142
- open source package for Remote Desktop Protocol, 82
- OpenSSH
- empty passwords, 106
- login allowing, 108
- SSH client logins, 74
- openssl command
- certificate authority servers, 73
- Certificate Signing Requests, 77
- OpenVPN
- network access, 74
- ports, 106
- Orca screen reader, 61
- orchestration
- agentless infrastructure, 183
- agents, 164, 198
- Ansible package, 162
- --origin option for repositories, 177
- output
- escape characters, 163
- to log files, 163
- logging, 76
- redirecting, , 81, 170
- variables, 177
- output files, setting, 80
- OVA files, 34
- overwriting files, 55
- OVF templates, 29
- ownership
- changing, 95, 118
- deleted accounts, 66
- displaying, 112, 149
- groups, 94–95
- inherited, 152
- IP addresses, 151
P
- packages
- available, 53
- caches, 52
- changes, 52
- information on, 53, 132
- installing, 48, 53, 129, 132
- repositories, 52, 72, 131
- searching for, 51, 188
- .tgz file extension, 53
- updating, 130
- packets
- pager, more command for, 84
- pam_cracklib.so module, 105
- pam_limits.so module, 122
- pam_listfiles.so module, 122
- pam_nologin.so module, 104
- pam_tally2 module, 115
- pam_unix.so module, 105
- parameters, positional, 180
- parentheses () for functions, 173
- parsing log-file entries, 196
- parted command, 12
- partition/mounted/var directory, 50, 187
- partition tables, updating, 151
- partitions
- changing, 12
- displaying, 128
- EFI system,
- GRUB Legacy configuration file,
- identifying,
- images, 94, 118
- information on, 34, 36
- initializing, , 131
- inodes, 134
- listing, 36
- MBR, 22
- names, 12
- non-swap, 132
- RAID arrays, 24
- swap, , 134, 143, 192
- UUIDs, 11
- partprobe command, 151
- passwd command, 64
- password-based logins, locking out, 63
- passwords
- age limits, 121
- boot prevention, 114
- bootloaders, 110
- change dates, 64, 69
- empty, 106
- file, 64
- local authentication, 156
- PAM authentication, 105
- recovering, 128
- skipping, 99
- strength, 105
- paste command delimiters, 81
- patch command for file backups, 198
- patch files, whitespaces in, 197
- paths
- PBKDF2 function, 101
- pcap format for traffic, 151
- pci-0000 file, 25
- PEM format, 105
- performance
- CPU, 191
- graphing, 143
- historical data, 151
- monitoring, 69
- polling interval, 145
- permissions
- bash scripts, 154
- directories, 153
- displaying, 94
- files, 112
- inheriting, 111
- new files, 95
- octal notation, 120
- rsync command, 198
- suid bit, 95
- symlinks, 59
- tar command, 197
- writing, 154
- Permissive mode in SELinux, 109
- PermitEmptyPasswords option, 106
- PermitRootLogin option, 74
- persistent volumes, 29
- pgrep command, 132
- physical volumes
- information on, 144
- logical volumes from,
- searches, , 132
- pidof sshd command, 148
- ping command
- bypassing routing tables, 198
- ECHO_REQUEST packets, 193
- emulating, 18, 139
- ICMP echo requests, 147
- ICMP packets, 136
- latency, 147
- packet policies, 146
- querying, 16
- PKI hashing algorithms, 113
- pkill command, 153
- Pluggable Authentication Modules
- authorization and authentication, 122
- configuration, 104
- failed login attempts, 115
- login prevention, 104
- password authentication, 105
- password strength, 105
- policies, 149
- required, 109
- user limits, 122
- policies
- INPUT chain, 106
- PAM, 149
- SELinux configuration, 109
- polling interval for performance, 145
- port forwarding in SSH, 76
- port-to-protocol translations, 98
- ports
- configuring, 97
- CUPS administrative web interface, 67
- CUPS printing daemon, 152
- FibreChannel HBA, 149
- firewalls, 68
- ICMP, 98
- LDAP, 122, 189, 196
- MySQL, 82
- name servers, 97
- NTP, 108
- open, 141–142
- OpenVPN, 106
- slapd daemon, 104
- SMTP traffic, 97
- Squid, 104
- SSH, 122, 138
- telnet, 119
- VNC, 78
- well-known, 121
- positional parameters, moving, 180
- Postfix
- mail queues, 67
- TLS configuration formats, 105
- postqueue command, 67
- pound signs (#)
- command-line arguments, 177
- comments in scripts, 164
- PREROUTING chain, 105
- primary partitions,
- printenv command, 165
- printer groups, 68
- printf command, 84
- printing
- awk command, 195
- completed print jobs, 67
- environment, 165
- formatting, 84
- inode index numbers, 58
- libraries, 200
- lines, 54
- lists, 172
- ports, 152
- print queues, 67
- priority
- private addresses, 15, 136
- private keys
- Apache servers, 83
- certificate authority servers, 73
- SSH, 118, 120
- ssh-agent, 110
- privileges, minimum, 95
- /proc/bus/usb directory, 50
- /proc filesystem, 47
- /proc/meminfo file, 146
- /proc/mounts file, 32
- /proc/partitions file, 34
- procedure infrastructure automation, 178
- processes, 158
- AppArmor, 113
- hangups, 148
- IDs, 27, 132, 148
- killing, 133, 200
- limits, 141
- after logout, 85
- memory usage, 157, 200
- monitoring, 188
- priority, 133, 148
- restarting, 57, 133
- running, 158
- stopping, 56
- terminals, 84
- uninterruptible sleep, 152
- .profile file for time zones, 14, 181
- profiles
- progress indicators, 10, 188
- ps auwx command, 118
- ps aux command, 112
- ps command
- memory usage, 157, 200
- SELinux contexts, 115
- uninterruptible sleep, 152
- zombie processes, 157
- PS1 environment variable, 172
- pseudo-terminals devices, 115
- public keyrings for gpg, 101
- public keys in SSH, 98, 107, 120
- pubring.gpg file, 101
- pull command for repositories, 162
- purging caches, 33
- push command for network access, 74
- pvcreate command, , 131
- pvdisplay command, 25, 144
- pvscan command, 144
- PXE boot, 23
- pxelinux.0 file, 23
Q
- query destinations, changing, 154
- question marks (?) with less command, 58
- quotacheck command
- file creation, 135
- user quotas, 59
- quotas
- enabling, 135
- usage display, 59
R
-
escape characters, 198
- RAID arrays
- adapter detection, 153
- mdadm command, 26
- partitions, 24
- removing disks from, 156
- RAM disks, 20–21, 191
- Raspberry Pi interfaces, 76
- raw devices, 30
- rc file runlevels, 70
- read command for user input, 172
- read I/O requests, displaying, 34
- read-only variables
- readonly command, 170
- rebooting, 46
- reconfiguring locale variables, 178
- recovering passwords, 128
- recursive changes in chmod command, 169
- redirection
- to log files, 163
- output, , 81, 170
- STDERR, 56, 84, 170, 179
- STDIN, 79, 82, 182, 199
- STDOUT, 56, 84, 103, 182
- regions in time zones, 13, 189
- REJECT targets for iptables, 106
- relative paths, 30
- reloading BIND, 77
- Remote Desktop Protocol, 82
- remote names, obtaining, 177
- remounting filesystems, 11
- removable media, mount points for, 10
- removing
- blocks, 25, 192
- cron jobs, 196
- directories, 54
- environment variables, 171
- files, 84, 102
- groups, 65
- jobs, 63
- MAC addresses, 144
- modules, 21
- newlines, 145
- users, 62
- renice command, 148
- replaying events, 78
- reports scale, 147
- repositories
- changes to, 164
- cloning, 177, 195
- copying, 169
- creating, 163
- default branches, 169
- file versions, 167
- messages, 168
- metadata, 182
- packages, 131
- retrieving, 165
- retrieving objects from, 162
- shared, 180
- URLs, 72
- Yum, 130
- repquota command, 59
- requests
- reserved blocks, displaying, 12
- resize2fs command, 31
- resizing filesystems, 31
- restarting
- Apache servers, 75
- CUPS, 68
- processes, 57, 133
- restorecon command, 114
- rm command, 54
- rmmod command, , 35
- rndc command
- authentication, 103
- BIND name servers, 79
- rolling back merges, 176
- root user
- console logins, 111
- SSH logins, 116
- UIDs, 109
- route add command
- route command
- flags, 19
- name resolution, 144
- routes
- routing tables
- rpm command
- rpm kernel command, 52, 131
- rpm package file output location, 48
- rpm2cpio output location, 48
- RSA hashing algorithms, 113
- rss column for memory usage, 157
- rsync command
- archive mode, 71
- file modifications, 103
- file removal, 102
- file size, 193
- options, 108
- permissions, 198
- synchronization process, 103
- rsyslog command, 120
- rules
- iptables, 105–107
- reloading, 75
- runlevel command, 49
- runlevels
- displaying, 47, 49
- rc files, 70
- setting, 79
- single user mode, 46, 190
- --runtime-to-permanent option, 116
S
- Samba for NetBIOS name service requests, 74
- SANs (storage area networks),
- sar command
- CPU performance, 191
- historical performance data, 151
- SATA (Serial ATA) disks
- scale, report, 147
- scheduled jobs, 189
- scheduling
- scp command, 85, 117
- screen command, 133
- screen reader, Orca, 61
- Screen section for graphics card and monitor configurations, 60
- scripts
- directories, 27
- execute bit, 199
- execution, 162, 164
- file extensions, 164
- file removal, 84
- permissions, 154
- services, 46
- storage, 80
- terminating, 175
- scrolling logs, 94
- SCSI devices
- host adapter scans, 156
- support per bus, 49, 129
- search line for local client services, 18, 139
- searches
- files, 141–142
- package caches, 52, 131
- packages, 51, 188
- physical volumes, , 132
- SeatDefaults for guest logins, 135
- security bulletins, 116
- sed command, 53
- SELinux
- access denials, 155
- booleans list, 113
- configuration policies, 109
- contexts, 113, 115, 119, 152
- Enforcing mode, 110
- Permissive mode, 109
- SELINUXTYPE option, 109
- semicolons (;)
- case statement, 178
- chaining commands, 77, 174
- seq command, 172
- Serial ATA (SATA) disks
- server command for query destinations, 36, 154
- servers
- containers, 75
- queries, 17
- site-specific data, 94
- service accounts UIDs, 155
- service apache2 restart command, 75
- service reload command, 81
- service status command, 77
- service units, listing, 50, 187
- services
- boot times, 76
- displaying, 17, 47, 84, 100, 138
- executed on boot, 79
- loaded, 49, 187
- scripts, 46
- shutting down, 78
- stopping, 69
- sestatus command, 120
- set command for output redirection, 170
- setenforce command, 110
- setsebool command, 111
- SFTP
- file transfers, 116
- kickstart booting, 35
- sha1sum utility, 118
- SHA256withRSA option, 113
- shared IDs, 114
- shared libraries
- shared repositories, changes to, 180
- shebang lines for interpreter location, 171
- shells executed without initialization files, 60
- shift command for positional parameters, 180
- Shift key
- GRUB menu, , 186
- sticky keys, 61
- shim.efi bootloader, 22–23
- shims for UEFI, 23
- shutting down services, 78
- SIGKILL signal, 157
- SIGTERM signal, 200
- simultaneous login limits, 142
- single-user mode
- booting,
- passwords, 128
- runlevels, 46, 190
- setting, 49
- site-specific data
- size
- /boot partition,
- dumps, 24
- files, 154, 193
- filesystems, 31
- journal logs, 97
- partitions, 12
- requests, 155
- size column for memory usage, 157
- slapd.conf file, 122
- slapd daemon, 104
- SMTP traffic ports, 97
- snapshots for packets, 146
- SNMP servers firewall ports, 68
- sockets display, 17, 26, 138, 192
- software
- software tokens in two-factor authentication, 110
- sort command for unique items, 57
- sort order in top command, 143
- source code, committing, 168
- source command
- spawned windows in SSH sessions, 60
- SPF record for DNS queries, 19, 140
- Spice remote access, 79
- SQL commands, reading, 168
- square brackets [ ]
- file matching, 177
- while loops, 173
- Squid
- access control lists, 73–74
- ports, 104
- /srv directory, , 94
- ss command
- SSD disk location, 70
- SSH
- agentless infrastructure orchestration, 183
- authentication keys, 190
- connections, 197
- hosts, 111
- Kerberos authentication, 121
- keys, 98–99, 107, 120, 194
- login prevention, 141
- port forwarding, 76
- ports, 122, 138
- private keys, 118
- root user logins, 74, 116
- spawned window sessions, 60
- synchronization process, 103
- ufw traffic, 116
- X session connections, 61
- ssh-add command, 110
- ssh-agent command, 110
- ssh.conf file, 109
- ssh-copy-id command, 107
- ssh-keygen command, 98, 122, 194
- sshd.conf file, 109
- sshd_config file, 116
- SSL
- certificate authority servers, 73
- configuration, 108
- private keys, 83
- VPN clients, 113
- SSLCertificateKeyFile directive
- Apache servers, 83
- configuration, 104
- SSLEngine option, 104
- Start of Authority information, 18, 139
- startup commands for udev devices, 80
- STDERR, redirecting, 56, 84, 170, 179
- STDIN
- STDOUT
- steal column in involuntary wait scenario, 178
- sticky bits, enabling, 95
- sticky keys, enabling, 61
- stopping
- daemons, 81
- processes, 56
- services, 69, 78
- storage
- blob, 31
- host caches, 100
- libraries, 130
- mail, 187
- network configurations, 33
- storage area networks (SANs),
- strings, comparing, 165
- su command
- access restrictions, 113
- login environment, 101
- non-interactive sessions, 99
- subshells, command execution in, 166
- substitution operation, 53
- sudo command
- accounts, 96
- credentials, 190
- non-interactive mode, 119
- specific user, 99
- sudoedit command, 114
- suid bit for permissions, 95
- summary output with du command, 157
- suspending daemons, 83
- swap partitions
- creating, 192
- error corrections, 134
- identifying,
- skipping, 143
- swap space
- activating, 155
- deactivating, 143
- description, 130
- displaying, 133, 190
- information on, 143
- swapoff command, 143
- swapon command, 143, 155
- switch support in bonded-link aggregation, 33
- symlinks
- displaying, 186
- files, 28, 58
- permissions, 59
- World Wide Identifiers, 24
- synchronization process in SSH, 103
- /sys/block file, 153
- /sys/class/fc_host directory
- FibreChannel HBA, 149
- WWN for Fibre Channel, 71
- /sys/class/scsi_host/hostN/scan file, 156
- sysctl command
- boot values, 21
- kernel, 148
- parameters, 152
- settings display, 20, 200
- syslog level for informational messages, 66
- system BIOS for hard drive detection, 128
- system files, changes to, 117
- system log for DHCP server, 71
- system users, creating, 65
- system-wide cron files, 63
- systemctl command for killing processes, 200
- systemctl daemon-reload command, 70
- systemctl disable command, 69
- systemctl enable command, 47
- systemctl get-default command, 47
- systemctl isolate command, 49
- systemctl list-units command, 50
- systemctl mask command, 84
- systemctl restart command, 68
- systemctl status command, 49, 77, 187
- systemctl stop command, 81
- systemd-analyze command, 76
- systemd-journald service, 96
- systemd system
- configuration changes, 70
- configuration files, 49
- environment variables, 81
- journal, 96
- programs to execute, 47
- service units, 187
- targets, 197
- SystemMaxFileSize option, 97
- systemwide time zones, 14
- SysVinit service scripts, 46
T
- escape sequence, 176
- tabs
- cut command delimiter, 55
- horizontal, 176
- TACACS+ authentication, 117
- tail command
- lines printed, 54, 56
- logs, 94
- tar command
- excluding files, 102
- packages, 53
- permissions, 197
- tar file creation, 101
- uncompressing files, 102
- targets
- TCP
- CUPS administrative web interface portd, 67
- SMTP traffic ports, 97
- three-way handshakes, 98
- wrappers, 99
- TCP SYN packets and open ports, 142
- tcpdump command
- interfaces, 145
- packet snapshots, 146
- tcptraceroute command, 151
- telinit command, 49
- telnet ports, 119
- terminals for processes, 84
- terminating scripts, 175
- test command arguments, 173
- /tftpboot directory, 23
- .tgz file extension, 53
- third-party logging agents, 112
- three-way handshakes, 98
- 3D acceleration, 75
- ticket caches in Kerberos authentication, 112
- tilde character (~) for home directories, 173
- time zones
- timedatectl command, 13
- timeouts
- GRUB2 configuration files,
- troubleshooting, 151
- times
- command execution time, 31
- formats, 13, 175
- setting, 15
- timestamps, changing, 55
- TMOUT environment variable, 177
- tokens in two-factor authentication, 110
- top command
- process monitoring, 188
- sort order, 143
- touch command
- existing files, 55
- login prevention, 141
- tr command, 83
- TraceEnable setting, 85
- tracepath command, 139
- traceroute command
- live updates, 145
- TCP SYN packets in, 137
- vs. tracepath, 139
- unreachable hosts, 146
- traffic
- transferring files, 116
- Transport mode for VPNs, 115
- traversal of directories, 118
- troubleshooting
- connections, 140
- third-party logging agents, 112
- tshark command, 151
- tune2fs command
- error corrections, , 134
- extended options, 25
- maximum mount count, 199
- times filesystems mounted, 10–11
- two-factor authentication tokens, 110
- Type 1 hypervisors, 34
- type command, 171
- TZ line, 14, 181
U
- Ubuntu distribution Unity desktop, 80
- udev devices
- configuration, 46, 186
- network adapter names, 82
- startup commands, 80
- udev events, 70
- udevadm control command, 75
- udevadm monitor command, 70
- udevadm trigger command, 78
- UDP for OpenVPN, 106
- $UDPListen option, 97
- UEFI
- bootloaders, 22
- passwords, 114
- shims, 23
- ufw allow command, 116
- UFW configuration, 120
- UIDs
- authentication servers, 64
- root account, 109
- service accounts, 155
- ulimit command
- umask command, 94
- umount command
- remounting filesystems, 11
- unmounting filesystems, 73
- unreachable filesystems, 27
- unalias command, 178
- unallocated disk space, 30
- uncompressing files
- .gz files, 72
- lzma files, 94
- tar command, 102
- uninterruptible sleep process state, 152
- Unity desktop, 80
- unlink command, 84
- unloading modules, , 35
- unreachable hosts with traceroute command, 146
- until loops
- beginnings and ends, 180
- vs. while, 182
- update-grub command,
- updatedb command, 59
- updating
- Debian systems, 48
- kernel, 52, 131
- package caches, 52
- packages, 130
- partition tables, 151
- software, 129
- traceroute, 145
- upgrading kernel, 69
- uptime command for load average, 133, 200
- URLs for package repositories, 72
- USB devices
- Bluetooth, 85
- connection points, 129
- connections, 48
- hotplug, 47
- listing, 46, 128, 186
- mounting, , 12
- storage, 50
- user accounts. See accounts
- useradd command
- disabling accounts, 196
- groups, 64
- home directories, 63
- system users, 65
- userdel command, 62
- usermod command
- expiring accounts, 69
- home directories, 64
- password-based logins, 63
- printer groups, 68
- user names, 65
- usernames
- changing, 65
- IDs, 80
- listing, 54
- users
- automatic logouts, 177
- configuration files for login order, 60
- cron availability, 62
- cron scheduled tasks, 96
- files owned by, 66
- groups, 64
- information on, 65
- input by, 172
- limits, 99
- listing, 96
- logged in, 68–69, 142
- login allowing, 108
- login information, 73
- login limits, 122
- messages for, 102
- printer groups, 68
- process limits, 141
- quotas, 59, 135
- readable information, 61
- removing, 62
- system, 65
- /usr/lib/firewalld/zones directory, 110
- /usr/lib/modules file, 28
- /usr/share/zoneinfo directory, 13, 189
- usrquota command, 135
- UTC time for hardware clock, 15
- UTF-8 encoding for multibyte representation of characters, 13, 189
- UUIDs
- obtaining, 33
- partitions, 11
V
- values, displaying, 20
- /var/log/kern.log file, 28
- /var/log/secure file, 116
- /var/qmail/queue directory, 66
- /var/spool/cron/crontabs directory, 62
- /var/tmp/abrt directory, 78
- variables
- adding, 163
- availability, 195
- comparing, 176
- declaring, 166
- displaying contents, 162
- environment. See environment variables
- expansion, 183
- local, 165
- output, 177
- read-only, 170, 175
- setting, 174
- verbose output in installations, 51, 187
- versions
- VFS (virtual filesystem), 31
- vgscan command, 144
- Vi editor
- insert mode, 57
- saving work, 56
- video cards, determining, 83
- video devices Spice remote access, 79
- <video> stanza for Spice remote access, 79
- virsh command
- domain information, 13
- hypervisors, 32
- virt-install tool, 33
- virtual filesystem (VFS), 31
- virtual machines, installing, 33
- <VirtualHost> directive, 77
- visudo editor, 100
- vmlinux, 28
- vmlinuz, 28
- vmstat command
- blocks, 142
- IO wait statistics, 200
- VNC
- default base port, 78
- services, 78
- volumes
- creation order,
- information on, 25, 144
- logical, 71, 131
- persistent, 29
- searches, 132
- VPNs
- SSL-based clients, 113
- Transport mode, 115
W
- w command for logged in users, 68–69, 142
- wa statistic for IO wait time, 200
- warning messages, suppressing, 103
- watching logs, 94
- WAYLAND_DISPLAY environment variable, 74
- Wayland sessions, 74
- wc command, 54
- web servers, enabling, 59
- welcome message, setting, 61
- Welcome section, 61
- well-known ports, 121
- wget command, 76
- wheel group for su command access, 113
- whereis command, 58
- which command, 58
- while loops
- whitespaces in patch file, 197
- who command, 73
- whoami command, 80
- whois command
- IP address ownership, 151
- legal disclaimer information, 156
- wildcard matches in /etc/hosts.allow file, 101
- windows, information on, 188
- wireless devices
- link status, 71
- parameters, 26, 83
- World Wide Identifiers (WWIDs)
- /dev/disk/by-multipath directory, 35
- symlinks, 24
- :wq command in Vi editor, 56
- WWN for Fibre Channel, 71
X
- X server connections, 135
- X sessions, SSH connections in, 61
- X11Forwarding option
- SSH connections, 61
- X11 forwarding, 100
- xfs_check command, 24
- xfs_growfs command, 11
- xfs_info command, 11
- xfs_metadump command, 10, 188
- xfsdump command, 24
- xfsrestore command, 24
- xhost command, 135
- Xmas scans, 146
- XML standard for OVF templates, 29
- xorg.c file, 82
- xrdp package, 82
- xwininfo command, 188
- xz command, 94
Y
- YAML format
- EC2 instances, 32
- /etc/netplan directory, 34
- extension, 179
- .yml extension, 179
- yum deplist command, 51, 187
- yum install command, 48, 129
- Yum repositories, 51, 130
- yum search command
- package caches, 52
- partitions, 131
- 0xFD partitions for RAID arrays, 24
Z
- zip command, 118
- zombie processes, finding, 157
- zone transfers, 19, 140, 193
- zones, firewalld, 110
- zypper info command, 53
..................Content has been hidden....................
You can't read the all page of ebook, please click
here login for view all page.