_                      __           __ __
                      (_)____          _____ / /_   ___   / // /
                     / // __ \ ______ / ___// __ \ / _ \ / // / 
                    / // /_/ //_____/(__  )/ / / //  __// // /  
                 __/ / \____/       /____//_/ /_/ \___//_//_/   
                /___/                                           

A basic UNIX shell implementation in C

jsh is free software and makes use of the GNU Readline library for input line editing and history.

Configuration files:

• ~/.jshrc: file containing commands to be executed at login
• ~/.jsh_history: containing the command history auto loaded and saved at login/logout
• ~/.jsh_login: file containing the ASCII welcome message auto printed at login of an interactive session

Supported options:

• -h, --help display the help message
• -d, --debug turn printing of debug messages on
• -n, --nodebug turn printing of debug messages on
• -c, --color turn coloring of jsh output messages on
• -o, --nocolor turn coloring of jsh output messages off
• -f, --norc disable autoloading of the ~/.jshrc file
• -l, --license display licence information

The following grammar is currently supported.

 input  :=    expr

 expr   :=    <space>expr         // expr is a logical combination of cmds
              expr<space>
              expr #comment
              "expr"
              (expr)
              expr ; expr
              expr && expr
              expr || expr
              cmd

 cmd    :=    cmd | cmd           // cmd is the unit of truth value evaluation
              cmd >> path         // note: pipe redirection get priority over explicit redirection
              cmd 2> path
              cmd > path
              cmd < path
              cmd &               *TODO not yet implemented
              comd

 comd   :=    comd option         // comd is the unit of fork / built_in
              alias               // note priority: alias > built_in > executable
              built_in
              executable_path     // relative (using the PATH env var) or absolute

 alias  :=    (expr)              // alias is a symbolic linkt to an expr

Currenly supported built_ins:

• cd
• color
• debug
• exit
• history
• shcat
• alias // syntax: alias key "value with spaces"
• unalias

To compile jsh, clone this respository, cd into it and execute make. See the wiki page for more info.