bash

See more info in the Options cheatsheet.

Help

$ bash --help

GNU bash, version 5.0.17(1)-release-(x86_64-pc-linux-gnu)
Usage:  bash [GNU long option] [option] ...
        bash [GNU long option] [option] script-file ...

GNU long options:
        --debug
        --debugger
        --dump-po-strings
        --dump-strings
        --help
        --init-file
        --login
        --noediting
        --noprofile
        --norc
        --posix
        --pretty-print
        --rcfile
        --restricted
        --verbose
        --version

Shell options:
        -ilrsD or -c command or -O shopt_option         (invocation only)
        -abefhkmnptuvxBCHP or -o option
Type `bash -c "help set"' for more information about shell options.
Type `bash -c help' for more information about shell builtin commands.
Use the `bashbug' command to report bugs.

bash home page: <http://www.gnu.org/software/bash>
General help using GNU software: <http://www.gnu.org/gethelp/>

Run script

Current shell

Run in current shell (ZSH, Bash, etc.) Any changes to directory, variablets, etc. will be persisted. It effectively copies the contents of the script and runs them at the current level.

$ source script.sh

Subshell

This will not persist anything.

Run script by name:

$ bash script.sh

Run commands with string:

$ bash -c 'echo Hello'
Hello

Separate with newlines:

$ bash -c 'echo Hello
echo World'
Hello
World

Run as root:

$ sudo bash -c 'echo Hello && echo World'
Hello
World

See sudo for more info.