Track certain parameters on some command

Question

Let's say that I have a command git branch (always with a couple of words) for example.

What I want is to keep track of when this command is executed with arguments. For example, if I execute the command git branch develop without errors, I want to save develop on a file.

I tried to overwrite git command on my .bash_profile, something like this:

git () {
    if [ $# -eq 3 ]
    then
        git $@
        echo $2 > /path/tacked_parameters.txt
    else
        git $@
    fi
}

But seems that does not work well. Is there any way to do this?

Answer 1

You've got a few problems here:

• your git function is calling itself recursively instead of the original git command.
• you're using $@ unquoted which doesn't make any sense whatsoever
• you're leaving other variables unquoted, asking the shell to split+glob them.
• you're using echo for arbitrary data.
• you're losing the exit status of the original git command.
• you're overwriting your log file upon each invocation.
• you're putting function definitions in your ~/.bash_profile which is meant to customize your login session, not your shell and is normally not read by non-login bash invocations.

You'd want something like:

git() {
  if [ "$#" -eq 3 ]
  then
    local ret
    command git "$@"; ret=$?
    printf '%s\n' "$2" >> /path/tacked_parameters.txt
    return "$ret"
  else
    command git "$@"
  fi
}

That is:

• quote your variables,
• use command to run the git command,
• save the exit status of git in a local variables an return it on exit,
• use >> instead of > for redirection to the log file.
• use printf instead of echo.
• and put that in your ~/.bashrc instead (making sure your ~/.bash_profile is sourcing ~/.bashrc as login bash shells don't read ~/.bashrc by default (a bash bug/misfeature)). Unless you want to export that git function (with export -f git) in case you also want bash scripts that call git to call that function.