The login shell executes /etc/profile if this file exists
and is readable.
This file does the shell setup that applies to all users, so you'll be
interested in it if you're the system administrator; you
need to log in as root in order to edit it.
The /etc/profile file:
- sets the HOSTNAME and
SYSNAME environment variables if they aren't already set
- adds the appropriate directories to the PATH
environment variable (the root user's PATH
includes directories such as /sbin that contain system
executables)
- sets up the file-permission mask (umask); see
“File ownership and permissions”
in Working with Files
- displays the date you logged in, the “message of the day”
(found in /etc/motd), and the date you last logged in
- sets the TMPDIR environment variable to /tmp
if it isn't already set.
- runs any scripts in the /etc/profile.d directory
as “dot” files (i.e., instead of executing them as separate
shells, the current shell loads their commands into itself).
For more information about dot files, see
“. (dot) builtin command”
in the documentation for ksh in the
Utilities Reference.
If you have a script that you want to run whenever anyone on the system
runs a login shell, put it in the /etc/profile.d directory.
You must have root-level privileges to add a file to
this directory.
For example, if you need to set global environment variables or run
certain tasks when anyone logs in, then this is the
place to put a script to handle it.
If you're using sh as your login shell, make sure that
the script has a .sh extension.