Ad-Hoc Commands and Modules

Ad-hoc commands are one-line Ansible commands that let you perform quick tasks without writing a playbook. They are ideal for testing, troubleshooting, and one-off operations. Every ad-hoc command uses a module --- the building block of all Ansible automation.

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Ad-Hoc Command Syntax

ansible <host-pattern> -i <inventory> -m <module> -a "<arguments>"

Flag	Description
-i	Path to the inventory file
-m	The module to use
-a	Arguments to pass to the module
-b	Enable become (privilege escalation / sudo)
-u	Remote user
-k	Prompt for SSH password
-K	Prompt for become (sudo) password
-f	Number of parallel forks (default: 5)
-v	Verbose output (-vv, -vvv, -vvvv for more detail)

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The ping Module

The ping module is the simplest way to verify connectivity --- it is not an ICMP ping, but an Ansible-level connectivity test:

# Test all hosts
ansible all -m ping

# Test a specific group
ansible webservers -m ping

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Common Modules

command Module (Default)

Runs a command on the managed node. This is the default module if -m is not specified:

ansible webservers -a "uptime"
ansible webservers -a "df -h"
ansible webservers -a "free -m"

Note: The command module does not support shell features like pipes, redirects, or environment variables. Use the shell module for those.

shell Module

Like command, but runs through /bin/sh, supporting pipes and redirects:

ansible webservers -m shell -a "cat /var/log/syslog | tail -20"
ansible webservers -m shell -a "echo $HOSTNAME"

copy Module

Copy files from the control node to managed nodes:

# Copy a file
ansible webservers -m copy -a "src=/local/path/app.conf dest=/etc/app/app.conf owner=root mode=0644"

# Create a file with inline content
ansible webservers -m copy -a "content='Hello World' dest=/tmp/hello.txt"

file Module

Manage files, directories, and symlinks:

# Create a directory
ansible webservers -m file -a "path=/opt/app state=directory owner=deploy mode=0755"

# Create a symlink
ansible webservers -m file -a "src=/opt/app/current dest=/opt/app/latest state=link"

# Delete a file
ansible webservers -m file -a "path=/tmp/old-file.txt state=absent"

apt Module (Debian/Ubuntu)

Manage packages on Debian-based systems:

# Install a package
ansible webservers -b -m apt -a "name=nginx state=present"

# Install latest version
ansible webservers -b -m apt -a "name=nginx state=latest"