Bourne and Korn Shell Configuration Files

1. The /etc/profile file.

   This is an ASCII text file that contains commands and shell procedures and sets environment variables that are appropriate for all users on the system. This file is executed by the login process.

   A sample /etc/profile is shown below:

   # Ignore keyboard interrupts.

   trap "" 2 3

   # Set the umask so that newly created files and directories will be readable

   # by others, but writable only by the user.

   umask 022

   case "$0" in

   *su )

   # Special processing for ''su -'' could go here.

   ;;

   -* )

   # This is a first time login.

   #

   # Allow the user to break the Message-Of-The-Day only.

   trap "trap '' 2" 2

   cat -s /etc/motd

   trap "" 2

   # Check for mail.

   if /bin/mail -e

   then

   echo "you have mail"

   fi

   ;;

   esac

   trap 2 3

   In the example, several commands are executed:

   • keyboard interrupts are trapped

   • the user's umask is set to 022--full permission for the user, read and execute permission for members of the user's group and others on the system

   • if the user is logging in for the first time, the message of the day (/etc/motd) is displayed, and the user is notified if he or she has mail

2. The individual user's .profile.

   This file is similar to /etc/profile, but is kept in the user's home directory. The .profile file can contain additional commands and variables that further customize a user's environment. It is executed whenever a user spawns a subshell.

   A sample .profile is shown below:

   # Set the interrupt character to <Ctrl-C> and do clean backspacing.

   stty intr '' echoe

   # Set the TERM environment variable

   eval 'tset -s -Q'

   # List files in columns if standard out is a terminal.

   ls() { if [ -t ]; then /bin/ls -C $*; else /bin/ls $*; fi }

   PATH=:/bin:/usr/bin:/usr/sbin:/usr/bsd:$HOME/bin:.

   EDITOR=/usr/bin/vi

   PS1="IRIX> "

   export EDITOR PATH PS1

   In this example:

   • the interrupt character is set to <Ctrl-C>

   • the TERM environment variable is set with tset(1)

   • a function called ls is defined so that when the user enters ls to list files in a directory, and the command is issued from a terminal or window, the ls command is invoked with the -C option

   • the environment variables PATH and EDITOR are set

   • the user's prompt (PS1) is set to IRIX>