notes/IT/Scripting.md

Marking a script as executable

Sometimes, you may need to mark a script as an executable to run it. On Linux, this can be accomplished by chmod +x [FILE], where [FILE] is the file you want to mark as executable. To unmark a file as executable, use chmod -x

The shebang

There are various shells with their own language syntax (sh, bash, fish, etc). Therefore, more complicated scripts will indicate a particular shell by specifying the absolute path to the interpreter as the first line, prefixed by #! like this:

#!/bin/sh
echo "Hello, World!"

#!/bin/sh means that this script can be executed by the binary located at /bin/sh, and so the reader knows this is a sh(ell) script.