Tutorial by Examples

To execute a script file with the bash interpreter, the first line of a script file must indicate the absolute path to the bash executable to use: #!/bin/bash The bash path in the shebang is resolved and used only if a script is directly launch like this: ./script.sh The script must have exe...

To execute a script file with the bash executable found in the PATH environment variable by using the executable env, the first line of a script file must indicate the absolute path to the env executable with the argument bash: #!/usr/bin/env bash The env path in the shebang is resolved and used...

There are two kinds of programs the kernel knows of. A binary program is identified by it's ELF (ExtenableLoadableFormat) header, which is usually produced by a compiler. The second one are scripts of any kind. If a file starts in the very first line with the sequence #! then the next string has to...