Running scripts from another directory

Quite often, the script I want to execute is not located in my current working directory and I don't really want to leave it.

Is it a good practice to run scripts (BASH, Perl etc.) from another directory? Will they usually find all the stuff they need to run properly?

If so, what is the best way to run a "distant" script? Is it

. /path/to/script

or

sh /path/to/script

and how to use sudo in such cases? This, for example, doesn't work:

sudo . /path/to/script

Solution 1:

sh /path/to/script will spawn a new shell and run she script independent of your current shell. The source (.) command will call all the commands in the script in the current shell. If the script happens to call exit for example, then you'll lose the current shell. Because of this it is usually safer to call scripts in a separate shell with sh or to execute them as binaries using either the full (starting with /) or relative path (./). If called as binaries, they will be executed with the specified interpreter (#!/bin/bash, for example).

As for knowing whether or not a script will find the files it needs, there is no good answer, other than looking at the script to see what it does. As an option, you could always go to the script's folder in a sub-process without leaving your current folder:

(cd /wherever/ ; sh script.sh)

Solution 2:

You can definitely do that (with the adjustments the others mentioned like sudo sh /pathto/script.sh or ./script.sh). However, I do one of a few things to run them system wide to not worry about dirs and save me useless extra typing.

1) Symlink to /usr/bin

ln -s /home/username/Scripts/name.sh /usr/bin/name

(be sure there is no overlapping name there, because you would obviously override it.) This also lets me keep them in my development folders so I can adjust as necessary.

2) Add the Scripts dir to your path (using .bash_profile - or whatever.profile you have on your shell)

PATH=/path/to/scripts/:$PATH

3) Create Alias's in the .bash_profile in ~/.bash_profile add something like:

alias l="ls -l"

As you can tell, the syntax is just alias, digits you want to act as a command, the command. So typing "l" anywhere in the terminal would result in ls -l If you want sudo, just alias sl="sudo ls -l" to note to yourself l vs sl (as a useless example).

Either way, you can just type sudo nameofscript and be on your way. No need to mess with ./ or . or sh, etc. Just mark them as executable first :D