42sh

Features

Aliases

Making up new commands as abbreviations for longer, more complex commands:

• alias lists all aliases
• alias name displays the value of this alias
• alias name [word_list] sets word_list as the value for name
• unalias [name1, name2...] remove the given aliases. * is supported.

Special aliases supported:

• precmd runs just before each prompt is printed
• cwdcmd runs after every change of working directory

History

Invoking previous commands using command history:

• !! executes the previous command
• !n executes the nth command that was previously executed
• !-n executes the command that was executed n commands ago
• !string executes the most recently executed command that starts with string
• !?string executes the most recently executed command that contains string
• history [nb] displays the previous commands (up to nb if specified) with their index and time of execution (hh:mm)

A .42sh_history file is also stored in the user's home folder to have a persistent history between sessions.

Job control

• fg id brings the specified job into the foreground, where id is the job ID
• jobs lists all jobs

Line editing

• ↑ and ↓ to select a command from the history to edit/execute
• ← and → to move in the input and edit it
• CTRL + L to clear the screen

Local environment

Variables specific to the current shell:

• set var = val creates/updates var with val
• set var1 var2 ... creates/updates several variables with empty values
• -r is an option that can be used with set for a read-only variable, which means that you won't be able to use set or unset on it again.
• unset var1 var2 ... removes the given variables

Preloaded variables:

• cwd for the current working directory (will be updated when you change directory)
• euid for the effective user id
• euser for the effective username
• gid for the user's group id
• group for the user's group name
• history explained below, set to 100 by default
• home for the user's home directory
• owd for the old working directory (will be updated when you change directory)
• uid for the user id
• user for the username

Special variables supported:

• ignoreeof to disable EOF shell exit if set to 0 or empty. If set to a number n, the shell will exit on the nth consecutive EOF.
• history to set a limit of commands display by the builtin of the same name.

Developers

Florian Lauch	Léa Guillemard	Dorian Moy	Reza Rahemtola