topic Re: How do I script the directory in which this script is located? in Operating System - HP-UX

How do I script the directory in which this script is located?

Stuart Abramson — Wed, 22 Dec 2004 15:00:30 GMT

We have scripts that we move around from machine to machine.

They can be in:
/usr/local/bin/
/opt/local/bin/
/usr/contrib/bin

How can I script definitively where they are from within the script. You can't just go $PWD, because if that will give you where you are sitting right now. You can't go "whence" because that may turn up more than one of them. Also, the location may be some other place not in your path.

I think that you can use some combination of "basename" or "dirname" or something like that.

Re: How do I script the directory in which this script is located?

Tom Danzig — Wed, 22 Dec 2004 15:04:00 GMT

in script:

which $0

Re: How do I script the directory in which this script is located?

Tom Danzig — Wed, 22 Dec 2004 15:15:58 GMT

EDIT: If you only want the directory, use:

dirname `which $0`

Re: How do I script the directory in which this script is located?

Stuart Abramson — Wed, 22 Dec 2004 15:46:36 GMT

I think that "which" only works for c shell users. It takes the path/environment from .cshrc.

Since I'm a ksh user, it doesn't work for me. It says "no xxxx in and lists my path (correctly - but it can't find xxxx which is right there in the path.)

Re: How do I script the directory in which this script is located?

Patrick Wallek — Wed, 22 Dec 2004 15:50:29 GMT

which SHOULD work for any shell in HP-UX. A better option may actually be to use whence.

# whence xxxx

Re: How do I script the directory in which this script is located?

Tom Danzig — Wed, 22 Dec 2004 15:53:34 GMT

/usr/bin/which should work for any shell. whence is actually a shell built-in and would not be available in csh.

Re: How do I script the directory in which this script is located?

c_51 — Wed, 22 Dec 2004 18:39:54 GMT

i've always used:
program="${0:##*/}"
path="${0:%/*}"

for posix type shells

Re: How do I script the directory in which this script is located?

c_51 — Wed, 22 Dec 2004 19:51:48 GMT

I guess i left out a bit,

path="${0:%/*}"
#
# find where I am, absolute path to this directory
#
oldDir=$(pwd)
cd $path
mydir=$(pwd)
cd $oldDir

Re: How do I script the directory in which this script is located?

Bill Hassell — Wed, 22 Dec 2004 23:23:12 GMT

This is going to be tricky because $0 is the name used to start the script. The basename will be the name of the script but unless the user uses a full pathname, $0 will report just what was used to start it. It might be: scriptname ./scriptname ../scriptname bin/scriptname, etc.

You'll need to test the dirname results. If it starts with /, then you have a full pathname and you know where it came from. If dirname is empty or contains relative locations, then the location can be determined with the construct:

MYNAME=${0##*/}
MYDIR=$(dirname $0)
if [ $(echo $MYDIR | cut -c 1) != / ]
then
MYFULLPATH=$(whence ./$MYDIR/$MYNAME)
else
MYFULLPATH=$MYDIR/$MYNAME
fi
echo $MYFULLPATH

In this snippet of code, we use the shell to perform basename, but use dirname rather than ${0:%/*}. The reason is that if the script is started by the simple name, the shell construct returns the basename rather than . so we use dirname to make sure it is really a valid directory reference.

The way it works is to put ./ in front of whatever dirname is found in $0. Then run the ./DIRNAME/SCRIPTNAME through whence and it returns a useable full pathname. Note that you may see an extra ./ in $MYFULLPATH but it is still a valid directory reference.

This sample has been tested with:

/tmp/myscript
myscript
./myscript
../myscript
../bin/myscript
./././myscript

and so on. It should identify the full pathname of the script regardless of how it was invoked.

Re: How do I script the directory in which this script is located?

Dietmar Konermann — Thu, 23 Dec 2004 07:17:43 GMT

Had that problem some time ago and just digged this from one of my scripts:

MYNAME=$(cd $(dirname $0); pwd -P)/${0##*/}

Best regards...
Dietmar.

Re: How do I script the directory in which this script is located?

Dietmar Konermann — Thu, 23 Dec 2004 07:19:52 GMT

Oh, just saw that you asked for the dierectory...that would be:

MYDIR=$(cd $(dirname $0); pwd -P)