16 Essential Commands Every Developer Should Know

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Table of Contents

1. ls
2. cd
3. pwd
4. mkdir
5. touch
6. rm
7. rm -r
8. cp
9. mv
10. cat
11. cat >
12. nano
13. ping
14. curl
15. wget
16. clear

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ls

Lists the contents of a directory.

• Syntax:

  ls [options] [path]
  

• Common Options:

  • -l — long format (detailed list)
  • -a — include hidden files (. prefix)
  • -h — human‑readable sizes (with -l)

• Example:

  # List everything, including hidden files, in long format
  ls -lah 
  

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cd

Changes your current directory.

• Syntax:

  cd [directory]
  

• Quick Tips:

  • cd alone takes you to your home folder.
  • cd - jumps back to the previous directory.

• Example:

  # Move into the “projects” folder inside your home
  cd ~/projects
  

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pwd

Prints the full path of your current working directory.

• Syntax:

  pwd
  

• Example:

  # Show where you are in the filesystem
  $ pwd
  /home/dhruvdankhara/projects
  

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mkdir

Creates new directories.

• Syntax:

  mkdir [options] directory_name
  

• Common Options:

  • -p — create parent directories as needed

• Example:

  # Create a nested path in one go
  mkdir -p ~/projects/blog/images
  

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touch

Creates an empty file or updates a file’s “last modified” timestamp.

• Syntax:

  touch [options] file_name
  

• Example:

  # Create a new file or update timestamp
  touch todo.txt
  

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rm

Removes (deletes) files.

• Syntax:

  rm [options] file_name
  

• Common Options:

  • -i — prompt before each removal

• Example:

  # Ask before deleting each file
  rm -i old_log.txt
  

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rm -r

Recursively removes directories and their contents.

• Syntax:

  rm -r [options] directory_name
  

• Common Options:

  • -f — force removal without prompts

• Example:

  # Force‑delete a folder and everything inside it
  rm -rf /tmp/my_temp_folder
  

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cp

Copies files or directories.

• Syntax:

  cp [options] source destination
  

• Common Options:

  • -r — recursive (for directories)
  • -i — prompt before overwrite

• Example:

  # Copy entire “assets” folder to “backup_assets”
  cp -r assets backup_assets
  

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mv

Moves or renames files and directories.

• Syntax:

  mv [options] source destination
  

• Common Options:

  • -i — prompt before overwrite

• Example:

  # Rename file or move to another folder
  mv draft.txt published/draft.txt
  

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cat

Displays the contents of a file.

• Syntax:

  cat [options] file_name
  

• Common Options:

  • -n — number all output lines

• Example:

  # Show file with line numbers
  cat -n script.sh
  

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cat >

Redirects your input into a file (overwriting existing content).

• Syntax:

  cat > file_name
  

• How It Works:

  1. Run cat > notes.txt.
  2. Type your text.
  3. Press Ctrl + D to save and exit.

• Example:

  $ cat > README.md
  # My Project
  
  This is a quick summary.
  (Ctrl+D)
  

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nano

A simple command-line text editor.

• Syntax:

  nano [options] file_name
  

• Basic Shortcuts (at bottom of editor):

  • Ctrl + O — save file (Write Out)
  • Ctrl + X — exit nano
  • Ctrl + K — cut line

• Example:

  # Open or create “config.env”
  nano config.env
  

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ping

Checks connectivity to a host by sending ICMP echo requests.

• Syntax:

  ping [options] host
  

• Common Options:

  • -c <count> — send only <count> pings

• Example:

  # Ping google.com 4 times
  ping -c 4 google.com
  

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curl

Transfers data from or to a server.

• Syntax:

  curl [options] URL
  

• Common Options:

  • -O — save to a file named like the remote file
  • -I — fetch only HTTP headers

• Example:

  # Download image.jpg and save it locally
  curl -O https://example.com/image.jpg
  

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wget

Non‑interactive network downloader.

• Syntax:

  wget [options] URL
  

• Common Options:

  • -c — continue partial downloads
  • -q — quiet (no output)

• Example:

  # Continue downloading a large file if interrupted
  wget -c https://example.com/bigfile.zip
  

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clear

Clears the terminal screen.

• Syntax:

  clear
  

• Tip:

  • Use Ctrl + L as a shortcut in most terminals.

• Example:

  # Wipe the slate clean
  clear