How do I investigate commands being run when changing directories?

Question

I see “awk”, “find”, “sed”, and “which” momentarily appear in my Terminal window's title when changing directories.  (And not all of these always appear and there could be some I'm missing; I imagine this is because the title changes multiple times before the UI redraws.)

Although this is likely just some shell scripts and additions I've installed along the way (git status in PS1, perhaps), I'd like to investigate it just to make sure.  Is there an easy way to find out what script(s) are calling these?

Note on Context: I'm looking for a general investigative approach to discovering what is calling the sub-commands. My programmer's mindset makes me want a solution that would temporarily replace the sub-command with a stubbed one (à la #define/#undef) that would dump a stack trace at the point of call, then either call the original command or just abort. This approach may or may not be applicable to the shell.

Also: I'm primarily on OS X 10.8 using GNU bash 3.2.48.  I'm not sure if the system and bash version is completely relevant to the problem at-hand— a solution that works on my Debian instance as well would be nice.

Answer 1

With bash you can use set -o verbose:

$ set -o verbose
update_terminal_cwd; 
$ cd ~/Documents
cd ~/Documents
update_terminal_cwd; 

bash -lv would start a new login shell with the same option enabled.

For example update_terminal_cwd is defined in /etc/bashrc, which isn't indexed by Spotlight. But you can see the definition with declare -f update_terminal_cwd or set.

sudo opensnoop -n bash shows what files are accessed by processes named bash.

Answer 2

Your problem is not with the command itself. The problem is with the git status in PS1. Simply, every time you supply a command, PS1 becomes evaluated. In order for git status to appear, there is a batch of command executed in the current working directory. For example, it checks if the current directory is a git repo or not, then checks the branch name, may be some commit number or what status you decided to keep.

I am not quite sure if the solution suggested by Lauri will show such evaluations or not, but you may give it a shot.