scripting help

[slyth]

The following script is expected to update the $PATH environment variable with the result of 'pwd' command, however it does not work on CentOS 5.2:

#/bin/bash
export working_path=`pwd`
#echo $working_path
export PATH=$PATH:$working_path

[danielsmw]

Are you sure? Try echo'ing $PATH at the end of that script and see what it says. Note that (to the best of my knowledge, I could be wrong) a script like this will run in its own sub-shell of your original shell. Therefore, when this script exists, there will appear to be no change to the environment variables of your original, interactive shell.

If you want to change your "normal" shell, try just executing

export PATH=$PATH:`pwd`

at the command prompt. That should achieve the correct effect. (You can also do it this way in your script, eliminating the need for the working_path variable.)

[vsemaska]

As danielsmw mentioned when you normally execute a script it runs in a child process so the change isn't in your shell environment. To execute the script in the current shell environment use either method:

source /path/to/script

or

. /path/to/script

[slyth]

You're right the shell created by the script might not be allowing the $PATH to be updated within the "normal" shell.

Normal shell > calls > Shell generated by script.

The command suggested actually updates the PATH variable. Thanks for your help.

Are you sure? Try echo'ing $PATH at the end of that script and see what it says. Note that (to the best of my knowledge, I could be wrong) a script like this will run in its own sub-shell of your original shell. Therefore, when this script exists, there will appear to be no change to the environment variables of your original, interactive shell.

If you want to change your "normal" shell, try just executing

export PATH=$PATH:`pwd`

at the command prompt. That should achieve the correct effect. (You can also do it this way in your script, eliminating the need for the working_path variable.)

[i92guboj]

If you want to do this, use a function. You can define something like this on your .bashrc/.bash_profile,

# Function to add a path
# Usage: add_path <path>
add_path () {
  if [ "$PATH" == "${PATH/$1/}" ]
  then
    PATH="$1:$PATH"
    export PATH
  fi
}

Functions will run on the same shell you invoke them. So, you can just do:

add_path "/home/foo/my custom path"