When you first log in to your Unix account, you’ll be using the default shell on your system. The default shell, its features, and its options depend completely on what your system administrator specifies. Code Listings 3.1 and 3.2 show examples of how default shell prompts differ on two different systems.
xmission> echo $SHELL /bin/csh xmission> finger ejray Login name: ejray In real life: "RayComm Directory: /home/users/e/ejray Shell: → /bin/csh On since Jul 23 06:58:48 on pts/16 from → calvin.raycomm.com 1 minute 28 seconds Idle Time No unread mail No Plan. xmission> |
echo $SHELL
At your shell prompt, type echo $SHELL (capitalization counts!). This command tells Unix to display (echo) information about shell settings. This information, by the way, is contained in one of the environment variables, so the technical phrasing (which you might hear in Unix circles) is to “echo your shell environment variable.”
The system’s response will be the full path to your shell—something like /bin/csh, /bin/bash, or /bin/ksh.
[ejr@hobbes ejr]$ echo $SHELL /bin/bash [ejr@hobbes ejr]$ finger ejr Login: ejr Name: Eric J. Ray Directory: /home/ejr Shell: /bin/bash On since Wed Jul 22 07:42 (MDT) on tty1 → 3 hours 15 minutes idle On since Thu Jul 23 08:17 (MDT) on ttyp0 → from calvin No mail. Project: Working on UNIX VQS. Plan: This is my plan-work all day, sleep all → night. [ejr@hobbes ejr]$ |
✓ Tips
You can also use finger userid, substituting your login name for userid, to find out more about your shell settings. You can substitute any other userid and see comparable information about the other account holders. See Chapter 7 for more about finger. (Some systems do not support finger, because finger can be a bit of a security hole.)
You’ll find more information about different shells and their capabilities throughout this chapter.