touch — Create files and update timestamps

💬 "touch command"

touch creates an empty file, and if the file already exists, it only updates the modification time. It does not touch file contents.

In practice, it is often used as a configuration reload trigger or a deployment marker file.

• Concept: If the file does not exist, it is created as 0 bytes; if it exists, the access/modification time is updated to the current time.
• Left column: The created file name is generated as-is.
• Right column: For an existing file, the contents remain the same and only the Modify time changes.
• Specifying a time: You can specify the desired time with the -t and -d options.

Commonly used options

3 essential command combinations

• touch /var/www/html/reload.txt — Update the file the app watches to trigger a reload
• touch -c /opt/app/current/public/index.php — Update the timestamp only if the file exists (prevents mistakes)
• touch -d '2026-10-18 02:00' /tmp/marker — Create a marker file with a specific timestamp

💬 "Show me the verification procedure in a rehearsal environment"

These are common situations on live production servers, organized in order.

Step 1 · Create a marker file

Create a file to record the deployment time.

touch /opt/app/releases/20261018/.deployed

Step 2 · Reload trigger

Trigger a reload in an environment with a configuration watcher.

touch /etc/nginx/.reload

Step 3 · Verification

Check that the timestamp was updated.

stat -c '%n %y' /etc/nginx/.reload

How it is used in practice

1. Zero-downtime reload trigger

Situation — PHP-FPM detects configuration changes by file timestamp.

touch /etc/php/8.3/fpm/php.ini

Result — The configuration watcher re-reads the file even without content changes.

Point — Useful when you need to force a reapply even if the configuration content has not changed.

2. Mark deployment status

Situation — After deploying to multiple servers, you need to check which server is up to date.

touch /srv/app/.deploy-20261018 && stat -c '%y' /srv/app/.deploy-20261018

Result — You can record each server's deployment time in a file and compare them.

Point — If monitoring reads the file existence/timestamp, you can automatically inspect deployment status.

Cautions

• The year format for -t is often confusing between two-digit and four-digit years. -d is easier to read for specifying times.
• Arbitrarily changing the timestamp of production files can confuse backup tools (incremental backups).
• If you mistype a path without -c, an empty file will be created in the wrong location.

Actual execution output

This is the result of creating a marker file and checking its timestamp.

!touch command execution result: empty file creation and timestamp check

Live production server

Source (HTML): https://games.aidebatehub.com/programs/linux/filesystem/touch.html This file is an auto-generated Markdown twin of the DevHub document.