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@ingramj
Created August 31, 2009 23:17
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#!/usr/bin/env ruby
require 'readline'
require 'pp'
class Stsh
def initialize
@prompt = "-$ "
@aliases = {}
@running = false
set_traps
end
def set_traps
Signal.trap("INT") { print "\n#{@prompt}"; "DEFAULT" }
end
def readcmds
@running = true
while @running && line = Readline.readline(@prompt, true)
runcmd line
end
puts
end
def runcmd(s, a = false)
cmdline = s.split
cmd = cmdline[0]
if @aliases[cmd] != nil && a == false
runcmd(@aliases[cmd], true)
else
case cmd
when 'cd' then Dir.chdir(File.expand_path(cmdline[1]))
when 'alias' then add_alias(cmdline[1..-1])
when 'paliases' then pp @aliases
when 'exit' then @running = false
when '!' then puts(eval(cmdline[1..-1].join(' ')))
when 'logout' then puts "This had better not be a login shell! Try exit."
when 'help' then print_help
else
pid = fork
if pid == nil
# Child
exec s
else
Signal.trap("INT") { puts; "DEFAULT" }
Process.wait
set_traps
end
end
end
end
def add_alias(a)
@aliases[a[0]] = a[1..-1].join(' ')
end
def print_help
puts <<EOHELP
Stupid Shell:
cd - change directory
alias name body - add an alias
paliases - print defined aliases
exit - exit the shell
! - evaluate the rest of the line as ruby code
help - print this message
EOHELP
end
end
if __FILE__ == $0
s = Stsh.new
s.readcmds
end
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