Bash (an abbreviation of Bourne-Again Shell) is a shell used in various UNIX and GNU/Linux systems, but is also commonly used when referring to shell scripting.
The tutorials in this category are primarily focused on shell scripting.
Shell scripts may or may not have the .sh extension. It can sometimes be a good idea to include a (.sh) file extension, as this might help users identify the type of script more easily.
A script may include the following shebang as the first line in the file:
Which is a symbolic link to the preferred system shell on the system.
A shebang tells which interpreter the system should use to run the script.
For consistency, it is recommended to simply use #!/bin/sh when writing scripts, as this will automatically use the preferred POSIX-compatible shell on the system.
However, even when you have declared shell of the script correctly, you can still not be sure it will work on all systems, since it depends on which shell is available, and/or how the user calls the script. However, if care is taken while coding the script, it will usually be very portable.