Question

What is the best practice when running external utilities in shell scripts. For example if I want to run ‘gzip’ in multiple scripts ensuring that a specific gzip binary is used should I make the full path to the binary a variable and just use the variable thoughout the script?

GZIP=/home/me/bin/gzip
$GZIP somefile
$GZIP anotherfile

Or is it better practice to hard code the path for each call to the binary?

/home/me/bin/gzip somefile
/home/me/bin/gzip anotherfile

Or is it better to set and rely on the path?

PATH=/home/me/bin:$PATH
gzip somefile
gzip anotherfile

I’m not running the scripts as root therefore maintainability, and portability is more important than user security.

Answer 1

I think the first option is the best. You’ll find it or the similar:

SOMEPATH=/path/to/somewhere
EXEC_ONE=exec_foo
EXEC_TWO=exec_bar

$SOMEPATH/$EXEC_ONE --argument baz_file

in many system scripts.

You can use conditionals to test for existence and even compatibilty, available options, etc., and set the variables accordingly.