How to reset a variable value after running a certain command in bash

Question

i wanted to implement a cool feature for my PS1 prompt. I added \# string to show the command number of that command. My goal is that if a certain command is ran, the command number from \# to be set back to 1. I have some ideas but i don't know how to write it.
Is it possible to somehow export \# value as a variable, and when a command is run, the variable to be restored to the initial state. Actually this post says that its impossible.
If this doesn't work, can i create a counter that replaces \#, and then export it as a variable. That variable to be reset by a certain command.
https://www.baeldung.com/linux/bash-script-counter
Sorry i don't have enough knowladge in bash, hope i don't ask for the impossible. Thanks

@Zilog80 I have seen that post, but it does not answer my question. He wants his counter to reset every time he makes a mistake, in my case i want it to be reseted every time i run a certain command in shell. — George Rabus
– George Rabus, Commented Jun 25, 2021 at 12:53
In that case, using if [ "\$(history| tail -n1)" -ne "<your reset command>" ]; instead of if [ $? -eq 0 ]; will not do the trick ? Beware that you can't use !-1 in a prompt context. — Zilog80
– Zilog80, Commented Jun 25, 2021 at 13:16
My bad, if [ "\$(history| tail -n1| sed 's/^ *[0-9][0-9]* //')" -ne "<your reset command>" ]; , to get rid of the history line number. — Zilog80
– Zilog80, Commented Jun 25, 2021 at 13:26

Paul Hodges · Accepted Answer · 2021-06-25 13:38:38Z

1

I ran a quick test with a trap. This worked for me -

$: trap 'echo "$BASH_COMMAND"; [[ "$BASH_COMMAND" =~ ^:\ *reset ]] && trap -- debug' debug
set_titlebar
set_prompt
$: date
date
Fri Jun 25 08:29:26 CDT 2021
set_titlebar
set_prompt
$: : reset
: reset
$: date
Fri Jun 25 08:29:38 CDT 2021
$:

The trap checks $BASH_COMMAND for your key (I used : reset) and resets the trap when seen. Edit in whatever key and/or code you want.

answered Jun 25, 2021 at 13:38

Paul Hodges

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