This README is the one indexed from the repository at its latest ref, not from the tag for this version.

shell

Small simplistic helper class for executing shell commands in Crystal:

• run command,
• exit if it fails,
• return STDOUT of the command;
• optionally
  • allow to ignore failure
  • return STDERR of failed command.

Installation

Add this to your application's shard.yml:

dependencies:
  shell:
    github: maiha/shell.cr
    version: 0.4.2

Usage

require "shell"

Output of the shell command is available through #stdout and #stderr methods, numeric value of the exit status returned by the function #run.

Simplest usage of the #run method:

puts Shell.run("ls").stdout

If command fails Shell raises exception, but this behaviour can be overridden by fail_on_error variable:

puts Shell.run("command_with_non_zero_status", fail_on_error: false).stderr

Shell::Seq

Shell::Seq accumulates shell commands and those results. When an error occur, '#run' doesn't raise any errors and just skips latter commands. This is similar to Try monad concatinations.

shell = Shell::Seq.new
shell.run("mkdir /tmp/shell") if !Dir.exists?("/tmp/shell")
shell.run("git clone https://github.com/maiha/shell.cr.git", chdir: "/tmp/shell")
shell.run("ls /xxxxx")
shell.run("date")

shell.success?            # => false
shell.last.stderr         # => "ls: cannot access '/xxxxx': No such file or directory\n"
shell.map(&.cmd.split[0]) # => ["mkdir", "git", "ls"]
shell.log                 # shows `cmd`, `stdout`, `stderr` of all executed commands
# % mkdir /tmp/shell
# % git clone https://github.com/maiha/shell.cr.git
# Cloning into 'shell.cr'...
# % ls /xxxxx
# ls: cannot access '/xxxxx': No such file or directory

See test for further usage: spec/seq_spec.cr

Contributing

1. Fork it ( https://github.com/dmytro/shell/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Contributors

• dmytro Dmytro Kovalov - creator, maintainer