Jan Gehring > Rex > Rex::Commands::Run



Annotate this POD


View/Report Bugs
Module Version: v1.3.0   Source   Latest Release: Rex-1.4.0_03


Rex::Commands::Run - Execute a remote command


With this module you can run a command.


 my $output = run "ls -l";
 sudo "id";


run($command [, $callback])

run($command_description, command => $command, %options)

This function will execute the given command and returns the output. In scalar context it returns the raw output as is, and in list context it returns the list of output lines. The exit value of the command is stored in the $? variable.

 task "uptime", "server01", sub {
   say run "uptime";
   run "uptime", sub {
     my ($stdout, $stderr) = @_;
     my $server = Rex::get_current_connection()->{server};
     say "[$server] $stdout\n";

Supported options are:

  cwd           => $path
    sets the working directory of the executed command to $path
  only_if       => $condition_command
    executes the command only if $condition_command completes successfully
  unless        => $condition_command
    executes the command unless $condition_command completes successfully
  only_notified => TRUE
    queues the command, to be executed upon notification (see below)
  env           => { var1 => $value1, ..., varN => $valueN }
    sets environment variables in the environment of the command
  timeout       => value
    sets the timeout for the command to be run
  auto_die      => TRUE
    die if the command returns with a non-zero exit code
    it can be set globally via the exec_autodie feature flag
  command       => $command_to_run
    if set, run tries to execute the specified command and the first argument
    becomes an identifier for the run block (e.g. to be triggered with notify)
  creates       => $file_to_create
    tries to create $file_to_create upon execution
    skips execution if the file already exists


If you only want to run a command in special cases, you can queue the command and notify it when you want to run it.

 task "prepare", sub {
   run "extract-something",
     command     => "tar -C /foo -xzf /tmp/foo.tgz",
     only_notified => TRUE;

   # some code ...

   notify "run", "extract-something";  # now the command gets executed

If you only want to run a command if another command succeeds or fails, you can use only_if or unless option.

 run "some-command",
   only_if => "ps -ef | grep -q httpd";   # only run if httpd is running

 run "some-other-command",
   unless => "ps -ef | grep -q httpd";    # only run if httpd is not running

If you want to set custom environment variables you can do it like this:

 run "my_command",

    env => {
     env_var_1 => "the value for 1",
     env_var_2 => "the value for 2",

If you want to end the command upon receiving a certain output: run "my_command", end_if_matched => qr/PATTERN/;


This function checks if a command is in the path or is available. You can specify multiple commands, the first command found will be returned.

 task "uptime", sub {
   if( my $cmd = can_run("uptime", "downtime") ) {
     say run $cmd;


Run a command with sudo. Define the password for sudo with sudo_password.

You can use this function to run one command with sudo privileges or to turn on sudo globally.

 user "unprivuser";
 sudo_password "f00b4r";
 sudo -on;  # turn sudo globally on

 task prepare => sub {
   install "apache2";
   file "/etc/ntp.conf",
     source => "files/etc/ntp.conf",
     owner  => "root",
     mode  => 640;

Or, if you didn't enable sudo globally:

 task prepare => sub {
   file "/tmp/foo.txt",
     content => "this file was written without sudo privileges\n";

   # everything in this section will be executed with sudo privileges
   sudo sub {
     install "apache2";
     file "/tmp/foo2.txt",
       content => "this file was written with sudo privileges\n";

Run only one command within sudo.

 task "eth1-down", sub {
  sudo "ifconfig eth1 down";
syntax highlighting: