Sample configuration files

This page lists example configuration files interpreted by jsh. This should clarify the use of these files and sketch some possibilities for a custom jsh shell.

Sample ~/.jsh_login file

The content of this file is printed at login of an interactive session. Note this file is printed verbatim. Don't include shell commands to be executed here, put them in ~/.jshrc instead. Also note it is impossible to '#' comment lines here, as they are not interpreted by the shell.

If you want a mix of static strings and shell command output to be printed at login, include them in ~/.jshrc or source a separate file from there. Take a look at the ~/.jsh_logout file below for an example of static printf statements combined with shell command output.

Sample ~/.jsh_login file:

hello world! This is the proof of concept jsh shell
                                      _     __ 
                                     (_)__ / / 
                                    / (_-</ _ \
                                 __/ /___/_//_/
                                |___/

Sample ~/.jshrc file

The content of this file is interpreted line per line by the jsh shell at login of an interactive session. You can include any command that is understood by the jsh grammar here. Note a character preceded by a '' is escaped by jsh's shell expansion. Also note one can escape a arbitrary string by "quoting" it.

Sample ~/.jshrc file:

# This example file is part of jsh: A basic UNIX shell implementation in C
#
# ~/.jshrc : file containing jsh-shell commands executed by jsh on startup of an interactive
#   sesssion. This (example) file defines a custom prompt and loads some aliases.

################ 1. define a custom prompt ################

# a simple elegant prompt "user@hostname[exit_status]::pwd$ " with max_pwd_length 25
prompt "%u@%h[%s]::%d$ " 25

# a prompt with advanced coloring enabled (see the above screenshot)
# user@hostname[exit_status]::pwd [current_git_branch]git_status_char$ with max_pwd_length 15
prompt "%B%u%n@%F{black}%h%F{reset}[%S]::%f{yellow}%d%f{reset}%f{green}%g%f{resetall}%c%$ " 15 

################ 2. define some alias key value pairs ################
# SYNTAX:       alias key "a value with spaces"
# ALT SYNTAX:   alias key value\ escape\ if\ needed

alias ls        "ls --color=auto"       # (normal syntax example)
alias ll        ls\ -lh                 # (alt syntax example)
alias clr       clear                   # (non-space-value example)
alias grep      "grep --color=auto -i"
alias q         exit
alias h         "cat ~/.jsh_history"
alias test      "echo \"this is a \\\backslash\"; echo jo&&    pwd"

################ 3. Some more examples/ideas ################

# color on
# debug off

# echo "Hi from the rc_file" # note you can use ~/.jsh_login for printing welcome messages

# source some/file/path      # e.g. an external alias_file
# source ~/.jsh_logout       # as an example of a file mixing print and other shell commands

# echo -n "welcome to jsh version "
# jsh --version

Sample ~/.jsh_logout file

The content of this file is interpreted line per line by jsh at logout of an interactive session. It can for example be useful to print an exit message or clear the terminal screen, especially when nesting several jsh sessions. Note static output can be combined with the output of shell commands, as shown in the example below. (Currently this is still a bit messy as there's not yet support for a printf built_in and/or back ticks for command evaluation...)

Sample ~/.jsh_logout file:

# This example file is part of jsh: A basic UNIX shell implementation in C
#
# ~/.jsh_logout: a file containing jsh-shell commands executed by jsh when exiting
#   an interactive sesssion. This (example) file clears the screen, prints a blue ascii art
#   GNU and right to it the pid of the exited jsh and the number of history entries appended.
#
#     ,= ,-_-. =.
#    ((_/)o o(\_))          <- this is the GNU ascii art, taken from
#     `-'(. .)`-'           https://www.gnu.org/graphics/gnu-ascii2.html
#         \_/

################ 1. clear the terminal screen ################
clear

################ 2. print GNU ascii art and jsh-info ################
# NOTE: backspaces have to be '\\' escaped

printf "\\033[1;34m"        # toggle ascii art color (blue)
printf "  ,= ,-_-. =.\\n"
printf " ((_/)o o(\\_))"

printf "\\033[0m"           # toggle message color (normal)
printf "\\t############### jsh with pid "; pidof -s jsh | tr -d '\\n'
printf " exited ###############\\n"

printf "\\033[1;34m"        # restore ascii art color (blue)
printf "  `-'(. .)`-'"

printf "\\033[0m"           # toggle message color (normal)
printf "\\t############### added "; history --nb-entries | tr -d '\\n'
printf " history entries  ###############\\n"

printf "\\033[1;34m"        # restore ascii art color (blue)
printf "      \\_/\\n"
printf "\\033[0m"           # restore normal color

################ 3. Some more examples/ideas ################

# cat       # the shell won't exit till the user types ^D
# read      # (future) shell built_in that reads a single line from the user
# sl        # steam locomotive before exiting

This is how it looks in a terminal:

Sample ~/.inputrc file

jsh uses the GNU readline library for user input line editing and history. Readline's behavior can be customized by including commands in the ~/.inputrc file.

When jsh starts up, readline automatically reads the init file. From the readline doc:

The name of this file is taken from the value of the environment variable INPUTRC. If that variable is unset, the default is ~/.inputrc. If that file does not exist or cannot be read, the ultimate default is /etc/inputrc.

Note that in the future jsh will change some of readline's default settings, still allowing a user to override these (by re-loading the ~/.inputrc file after changing the defaults).

A sample ~/.inputrc file:

#### an ~/.inputrc file demonstrating some useful 'readline' settings ####

set completion-ignore-case on           # filename matching and completion in a case-insensitive fashion (default off)
set colored-stats on                    # display possible completions using different colors to indicate their file type (default off)
set print-completions-horizontally on   # display completions with matches sorted horizontally in alphabetical order, rather than down the screen (default off)
set show-all-if-ambiguous on            # list all matching possibilities immediately instead of hitting TAB twice (default off)
set expand-tilde on                     # tilde expansion is performed on word completion (default off)
set completion-query-items number       # set the number of possible completions that determine when the user is asked whether the list of possibilities should be displayed (default 100)
set history-size number                 # set the maximum number of history entries saved in the history list (default unlimited)