read only TMOUT variable – workaround to disable automatically exit shell when there is no activity

Question

We have here a read only Bash variable. I am not allowed to unset that variable.

$ echo $TMOUT
1800

As a workaround I wrote those lines (that my session don't exit)

#!/usr/bin/perl

$|++;
while (1) { print "\e[0n"; sleep 120; }

Is there an official package (rpm) that does similar (like above Perl code) in a CentOS7/RHEL7 repository? I don't like to open up a vim editor, I wish a command.

Answer 1

Add this to the start of your .bash_profile ?

if [ ! -z "$TMOUT" ]; then
  env -i bash --init-file ~/.bash_profile
fi

Beware the wrath of the sysadmins if you leave a gazillion old sessions running as a result of defeating their timeout rulings.

Answer 2

Here is the thing,
When the session variable is "Read Only" you have to replace the current shell process with the command by "exec"
So, the Answer to your question is:

$> exec env TMOUT=0 bash

But I recommend setting a higher timeout value

$> exec env TMOUT=3600 bash

Answer 3

You can issue perl commands from the command line...

perl -e '$|++; while (1) { print "\e[0n"; sleep 120; }'

or you could do the same in shell (a sh/bash example):

while sleep 120; do printf '\33[0n'; done

Or you could use watch:

watch -n 120 printf '\33[0n'

Answer 4

I my case, it is defined in /etc/profile.d/bash_autologout.sh:

TMOUT=1800
readonly TMOUT
export TMOUT

To find it, I did:

sudo find /etc/ -name "*" | xargs sudo grep "TMOUT" 2>&1 | grep -v "filter..."

Answer 5

export TMOUT=0

top

You will have some activity and your session will stay and you could see how long it runs.

Answer 6

Why aren't you switching to non-interactive session?

# TMOUT=0
-bash: TMOUT: readonly variable
# unset TMOUT
-bash: unset: TMOUT: cannot unset: readonly variable
# su
# export TMOUT=10
# unset TMOUT
#