Shell Programming and Scripting

Is it possible in Bash (or any other shell) to get a shell script to know it's own path without having to be part of $PATH or anything like that.

I need this cos i want the script to be able to rename the directory in which it resides.

is this possible?

use the 'pwd' command.

you could save the result of the pwd command in a variable, and then have awk or something else take away the last part of that string. so you would get
/some/directory/to_be_renamed

then have it chop off the to_be_renamed part and save that in another variable.

then you would have it do
mv $var_1 $var_2"new_name"

or something. check the syntax cause mine probably isnt correct.

unfortunately using pwd doesn't work unless i happen to be executing the command from the directory in which it resides. :-(

I made a test script

#! /bin/bash
echo `pwd` > ~/foo
exit 0

and found it i execute it from a shell it gives the pwd from the shell i am in and if i execute it outside of a shell (the way it needs to be execute in the way i want it to work) then it gives "/"

hmmm... i would think that the path from where you are executing the script from would be stored in some variable, but i dont know which one or if that is even the case.

anyone else know?

This is a very hard problem. The script may have been launched via a relatively non-standard exec system call. If that is not the case, $0 may be an absolute or relative path or an item that can be found by searching PATH. But with a non-standard exec, $0 may not be useful .

Another wrinkle involves the fd filesystem that some versions of unix have. These versions, and Solaris is one, allow suid shell scripts, but use an fd to prevent the shell from opening the script directly. $0 will be useless in this case.

One technique that might work is obtaining the pid of the shell running the script and using lsof on that. But even this assumes that the script was exec'ed one way or another. If you something odd like:
cat /path/to/script | ksh
the shell won't have the script open so finding the script becomes much tougher.

$0 worked :-)
thank you very much

I wanted the file to be executed as the app/contents/MacOS/executable file of a cocoa bundle (if that means anything too you.)


"i would think that the path from where you are executing the script from would be stored in some variable, but i dont know which one or if that is even the case. "

I believe pwd operated as an alias to "echo $PWD"

The working directory of programs launched by the Finder is always "/".