Shells: bash, sh, ksh, csh, exit

Shells

Shells are the basic interface between user and UNIX-kernel.

bash: GNU Bourne-Again SHell

sh: Bourne SHell

csh, tcsh: C shell with file name completion and command line editing

exit: Exit from current shell

Bash Shell

Bash is invoked as an interactive login shell,
or as a non-interactive shell with the --login option.

An interactive shell has standard input and output connected to the terminal.

It first reads and executes commands
from the file /etc/profile, then looks for
~/.bashrc, ~/.bash_profile, ~/.bash_login, and ~/.profile

Shell Scripting

You can invoke a shell with script file name.
The commandos in the script are then executed as they would be typed into a terminal.

>more hallo.sh

echo hallo

>bash hallo.sh
hallo
>