adding aliases for the new user after sudo'ing interactive from a script

Question

I was following the instructions in https://stackoverflow.com/questions/2135644/how-can-i-define-a-bash-alias-as-a-sequence-of-multiple-commands to create my own bash script. It is as follows:

sudo -u otheruser -i
alias cd1="cd /dir/one/"
alias cd2="cd /dir/two/"

I want these aliases to be available to otheruser. My goal is to run it as an executable but for testing I am sourcing it (to avoid the problem in https://stackoverflow.com/questions/2197461/how-to-set-an-alias-inside-a-bash-shell-script-so-that-is-it-visible-from-the-ou) like source ./myscript.

Even with doing that, the sudo works, but none of the following aliases are available (for otheruser). Do you think the aliases are being applied to the user that invoked this command, and not to the new user? Or is there some rule that commands in a script are ignored after sudo'ing to another user?

Answer 1

I think that the reason it doesn't work is that the two alias commands are run after bash session started by sudo finishes. You could make a test - source the script, when the new session starts press Ctrl-d to leave it and then in the original shell type:

$ type cd1
cd1 is aliased to `cd /dir/one/'
$ type cd2
cd2 is aliased to `cd /dir/two/'

I can achieve what you want with expect script but I'm not an expert on that so criticism is welcome:

#!/usr/bin/expect -f

spawn sudo -u otheruser -i
send "alias cd1='cd /dir/one/'"
send "\n"
send "alias cd2='cd /dir/two/'"
send "\n"

interact

Make sure you actually have expect installed before running this script.

You might be able to install expect and tcl (which it requires) using your system's package manager. If you need to install it manually, see the instructions for Expect at http://expect.sourceforge.net/. The README/INSTALL files for Expect point you at some locations for getting Tcl, but these seem out of date. However you can get a copy of Tcl from ActiveState.