Shell Programming and Scripting

Hi All,

I've searched through the forum for a solution to this problem, but I haven't found anything. I have 2 script files that are in different directories.

My first script, let's call it "/one/two/a.sh" looks like this:

Code:

#!/bin/sh
IN_DIR=`dirname $0`

CUR_DIR=`pwd`
cd $IN_DIR
A_DIR=`pwd`
cd $CUR_DIR

export $A_DIR
echo $A_DIR

Running that, gives me "/one/two/", and A_DIR is set to that value.


Now I have a second script in a different directory that sources this script. Let's call it "/hello/bye/b.sh"

Code:

#!/bin/sh
. /one/two/a.sh

echo $A_DIR

In this case, I DO NOT get "/one/two/", but instead: "/hello/bye/"

I guess this is because the $0 variable inside the first script becomes "b.sh" instead. I want the first script to always source the $A_DIR variable with the path of the script, and I do not want to rely on hard-coding it, nor using the "find" command.

Does anyone have any ideas? Any help would be great!

Thanks in advance!

pwd gives the current directory you are running the script in. It can be anything.

inside a.sh:

Code:

CUR_DIR=`dirname $0`

This ONLY works when you invoke a.sh with a full pathname, e.g. . /one/two/a.sh

Hi Jim, thanks for the reply.

I make some change directory calls inside a.sh, so that the pwd becomes dirname ${0}. The problem I think is that, I'm not invoking a.sh, but sourcing it inside b.sh:

Code:

#!/bin/sh
. /one/two/a.sh

echo $A_DIR

Let's say I invoke b.sh with the following:

/hello/bye/b.sh

Because a.sh makes the following call: dirname ${0}. It gets the path of the current value inside $0, which is actually "/hello/bye/b.sh", since that script is the one being actually invoked.

On the same lines of your last post, just a few recommendations...

Yes, that's the problem, you need to invoke a.sh script. Sourcing it, will cause it to get executed in the place of the current shell ( b.sh shell/environment), so every command of a.sh will get place in the b.sh shell /environment.
Secondly, in your situation you don't need export in a.sh. That will export the value of the variable A_DIR in the subshells of a.sh ( ex. if you invoke other scripts within a.sh, etc ... ). So to access the value of A_DIR in the outer script b.sh for further processing, one way of doing it, is through invoking a.sh and put the value of A_DIR in a temporary file inside a.sh :

a.sh script :

Code:

#!/bin/sh
IN_DIR=`dirname $0`

CUR_DIR=`pwd`
cd $IN_DIR
A_DIR=`pwd`
cd $CUR_DIR

echo $A_DIR > /hello/by/temp_file

and b.sh script :

Code:

#!/bin/sh

/one/two/a.sh
my_dir=`cat /hello/by/temp_file`

#To see the result
echo " This is A_DIR " $my_dir

# If you don't need the temp_file 
rm /hello/by/temp_file

Hope this helps.

There is rarely, if ever, a need to find the path to a script.

Put your scripts in a directory in your PATH and don't worry about where they are.