Os - Shell

Shell in an OS context (ie command line interpreter)

An OS shell is a language that provides access to the services of the operating system (kernel)

Each time we launch a shell, it creates a new process. A shell is just an interactive application providing a read-eval-print loop (REPL) in a terminal

• Dos (Win32 Shell Scripting) and Utilities
• Bash - Bash cli
• PowerShell
• Linux - Shell

Operating_system_shells

• remote access,
• tab-completion,
• command history

Every extension file has a color. See

dircolors

LS_COLORS='
rs=0:di=01;
34:ln=01;
36:mh=00:pi=40;
33:so=01;
35:do=01;
35:bd=40;
33;
01:cd=40;
33;
01:or=40;
31;
01:su=37;
41:sg=30;
43:ca=30;
41:tw=30;
42:ow=34;
42:st=37;
44:ex=01;
32:*.tar=01;
31:*.tgz=01;
31:*.arc=01;
31:*.arj=01;
31:*.taz=01;
31:*.lha=01;
31:*.lz4=01;
31:*.lzh=01;
...;

export LS_COLORS

• The colors numbers are Terminal Colors number