cp — copy files and folders

💬 "cp command"

• Concept: A basic Linux command that copies files or folders. It is often the first command used when backing up configuration files or copying deployment files to another path.
• Output behavior: Even on success, it prints nothing to the screen. So you often wonder, "Did it actually copy?"
• Recommended output in practice: If you add the -v option, it shows the copied result line by line, like 'main.go' -> 'main.go.bak'.
• Left column: Shows the path or name of the source to copy.
• Right column: Shows the path or name of the newly created copy.

Three essential command combinations

• cp file1 file2 — copy one file under a different name
• cp -r folder1 folder2 — copy a folder and all of its contents
• cp -a source target — copy while preserving permissions, owner, and timestamps (for backups)

It is also good to remember two more options that help prevent mistakes.

• -i — asks before overwriting.
• -n — skips without overwriting if the file already exists.

💬 "Show me one way to apply this"

Scenario: Before touching a working nginx configuration, back it up safely with a date appended.

Step 1: Check the original file

First, check whether the file to back up exists and how large it is.

ls -l nginx.conf

Step 2: Back up with a date appended

Use -a to preserve permissions and timestamps, and save a backup with today's date appended to the file name.

cp -a nginx.conf nginx.conf.$(date +%F).bak

Step 3: Verify the result

Compare the size and permissions of the original and the backup. If you also use -v, you can log the copy process.

ls -l nginx.conf*
cp -v nginx.conf nginx.conf.$(date +%F).bak

Actual execution screen

This is an example of copying a file with cp -v. The source being copied and the newly created copy are shown with an arrow.

!cp -v output: copying main.go to main.go.bak

Actual production server

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