Bash

Script

$ type script
$ chmod +x script
$ ./script
$ .script
$ source script
$ bash script

#!/bin/bash

Command Line

Everything is a file
255 Byte
The maximum length for a file name is 255 bytes.
The maximum combined length of both the file name and path name is 4096 bytes.
This length matches the PATH_MAX that is supported by the operating system.
Names are case-sensitive

Special chars to avoid in names/filenames

/   Never
\   Escaped
-   Never at beginning
[]  Escaped
{}  Escaped
*   Escaped
'   Escaped
"   Escaped

Wildcards

*  asterisk        | any char
?  question mark   | single char
[] square brackets | set of single char or a range of chars

List files and folders

ls
ls folder
ls ./folder
ls /path/folder
ls ~/folder
ls ~/folder/*.jpg
ls ~/folder/*txt*
ls -R folder (list of subfolders)
ls -l (single column)
ls -m (comma-separated list)
ls -a (hidden files and folders)
ls -F (file type)