REX(1)

💖 REX(1) 💖

okay bestie, pull up a chair 🫶 you're looking at rex, the manual page for the rex command. yes that's the manual name, it's literally in the title, we love a self-titled icon 💅

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✨ NAME ✨

rex — execute tasks defined in a Rexfile 🌸

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🎀 DESCRIPTION 🎀

The rex script can be used to execute tasks defined in a Rexfile from the command line. that's the whole job description and honestly? main character energy 👑

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🌈 SYNOPSIS 🌈

rex -h                      # Show usage
rex -T                      # List tasks
rex uname                   # Run the 'uname' task
rex -H server[01..10] uname # Run the 'uname' task on all the specified hosts
rex -G production uname     # Run 'uname' on hosts on the 'production' hostgroup
rex deploy --gracefully     # Pass '--gracefully' to the 'deploy' task

look at her go ✨ six whole vibes and every single one is a slay.

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👑 USAGE 👑

rex [<options>] [-H <host>] [-G <group>] <task> [<task-options>]
rex -T[m|y|v] [<string>]

and now the option buffet, no skipping, we're eating everything 🍓

• -b — Run batch
• -e — Run the given code fragment
• -E — Execute a task on the given environment
• -G, -g — Execute a task on the given server groups
• -H — Execute a task on the given hosts (space delimited)
• -z — Execute a task on hosts from this command's output
• -K — Public key file for the ssh connection
• -P — Private key file for the ssh connection
• -p — Password for the ssh connection
• -u — Username for the ssh connection
• -d — Show debug output
• -ddd — Show more debug output (includes profiling output)
• -m — Monochrome output: no colors
• -o — Output format
• -q — Quiet mode: no log output
• -qw — Quiet mode: only output warnings and errors
• -Q — Really quiet: output nothing
• -T — List tasks
• -Ta — List all tasks, including hidden
• -Tm — List tasks in machine-readable format
• -Tv — List tasks verbosely
• -Ty — List tasks in YAML format
• -c — Turn cache ON
• -C — Turn cache OFF
• -f — Use this file instead of Rexfile
• -F — Force: disregard lock file
• -h — Display this help message
• -M — Load this module instead of Rexfile
• -O — Pass additional options, like CMDB path
• -s — Use sudo for every command
• -S — Password for sudo
• -t — Number of threads to use (aka 'parallelism' param)
• -v — Display (R)?ex version

yes bestie, that's thirty-three of them. we counted. not one got left behind 😤

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🦋 Rexfile 🦋

When you run rex it reads the file Rexfile in the current working directory. A Rexfile consists of 2 major parts: configuration and task definitions. two parts, both essential, like you and your emotional support terminal 💖

🔥 Configuration 🔥

See all the available commands in Rex::Commands.

🧚 Simple authentication

user 'bruce';
password 'batman';
pass_auth;

🔐 Key authentication

private_key '/path/to/your/private/key.file';
public_key '/path/to/your/public/key.file';
key_auth;

📝 Define logging

logging to_file   => 'rex.log';
logging to_syslog => 'local0';

👯 Group your servers

Rex gives you the ability to define groups of servers. Groups can be defined in the Rexfile:

group 'frontends' => 'frontend01', 'frontend02', 'frontend[03..09]';

Groups can also be defined in separate files, like server.ini:

# server.ini
[frontends]
frontend[01..04]

# Rexfile
use Rex::Group::Lookup::INI;
groups_file 'file.ini'

See Rex::Group::Lookup::INI for more details, and check the Rex::Group::Lookup namespace for other formats. options for days, we love a namespace with range 🌈

💜 Other configuration 💜

timeout 10;    # ssh timeout
parallelism 2; # execute tasks in parallel

🌟 Defining tasks 🌟

A basic task looks like this:

# task description
desc 'This task tells you how long since the server was rebooted';

# task definition
task 'shortname', sub {
  say run 'uptime';
};

By default it will be targeted at the same host where rex is being executed.

You can also set a default server as the task's target:

desc 'This is a long description of a task';
task 'shortname',
  'frontend01',
  sub {
    say run 'uptime';
  };

or even a default server group:

desc 'This is a long description of a task';
task 'shortname',
  group => 'frontends',
  sub {
    say run 'uptime';
  };

The task options from the command line will be passed to the task as well:

# Rexfile
desc 'Get task options';
task 'get_task_options', sub {
  my $task_options = shift;
  my $option1 = $task_options->{option1};
};

# command line
rex get_task_options --option1=yes

the way that command line just hands its options straight to the task?? obsessed 💅

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⭐ TAB COMPLETION ⭐

Tab completion scripts are provided for Bash and Zsh in the share directory at https://metacpan.org/release/Rex/source/share. They provide completions for the available CLI options, hosts, groups, environments and tasks. no more typing the whole thing like a peasant, we're pressing Tab and letting the machine do the labour 🧚✨

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and that's the whole page, bestie!! this little beauty is perl v5.42.0, dated 2025-08-09, and yes she ate and left absolutely no crumbs 💖🎀🦋 periodt.