Text Editors (vim, nano, emacs basics)

Category: Intermediate Linux Commands
Type: Linux Commands
Generated on: 2025-07-10 03:12:17
For: System Administration, Development & Technical Interviews

---

Okay, here is a comprehensive cheatsheet for text editors (vim, nano, emacs) and intermediate Linux commands, tailored for sysadmins and developers, with the requested structure, style guidelines, and focus on practical, real-world scenarios.

Text Editors & Intermediate Linux Commands Cheatsheet (Sysadmin/Developer Focused)

I. Text Editors (vim, nano, emacs)

A. vim (Vi Improved)

1. Command Overview

• What: A powerful, highly configurable text editor. Modal editing (command mode, insert mode) allows for efficient text manipulation.
• When: Everyday text editing, configuration file editing, software development, scripting. Essential for remote server work where GUI editors are unavailable.

2. Basic Syntax

vim [options] [file...]

3. Practical Examples

• Open a file:

  vim my_file.txt

• Create a new file:

  vim new_file.txt

• Open multiple files:

  vim file1.txt file2.txt file3.txt

• Open a file at a specific line number:

  vim +10 my_file.txt  # Opens my_file.txt at line 10

4. Common Options

• -R: Read-only mode.
• +: Start editing at the last line.
• +[num]: Start editing at line num.
• -o: Open files in vertical splits.
• -O: Open files in horizontal splits.
• -d: Diff mode (compare two files).

5. Advanced Usage

• Using .vimrc: Customize vim’s behavior by editing ~/.vimrc. Example:

  " Enable syntax highlighting
  syntax on
  " Set tab width to 4 spaces
  set tabstop=4
  set shiftwidth=4
  set expandtab
  " Show line numbers
  set number

• Macros: Record and replay a sequence of commands.
  • q[char]: Start recording macro to register [char] (e.g., qa).
  • q: Stop recording.
  • @[char]: Execute the macro in register [char].
  • @@: Execute the last executed macro.
• Search and Replace with Regular Expressions:

  :%s/old_text/new_text/g  # Replace all occurrences of "old_text" with "new_text" in the entire file.
  :%s/^\s*//g             # Remove leading whitespace from all lines.
  :%s/\s+$//g             # Remove trailing whitespace from all lines.

• Splits and Tabs:
  • :sp: Split the window horizontally.
  • :vsp: Split the window vertically.
  • :tabnew: Open a new tab.
  • :tabn: Go to the next tab.
  • :tabp: Go to the previous tab.
  • Ctrl-w w: Switch between windows.

6. Tips & Tricks

• Essential Commands (Normal Mode):
  • i: Insert mode (before the cursor).
  • a: Append mode (after the cursor).
  • o: Open a new line below the current line.
  • O: Open a new line above the current line.
  • dd: Delete the current line.
  • yy: Yank (copy) the current line.
  • p: Paste after the cursor.
  • P: Paste before the cursor.
  • u: Undo.
  • Ctrl-r: Redo.
  • :w: Save the file.
  • :q: Quit vim.
  • :wq: Save and quit.
  • :q!: Quit without saving (discard changes).
  • G: Go to the end of the file.
  • gg: Go to the beginning of the file.
  • :[line_number]: Go to a specific line number.
  • /pattern: Search for pattern forward.
  • ?pattern: Search for pattern backward.
  • n: Find the next occurrence of the search pattern.
  • N: Find the previous occurrence of the search pattern.
  • :%s/old/new/g: Replace all occurrences of old with new.
  • .: Repeat the last command.
• Visual Mode:
  • v: Character-wise visual selection.
  • V: Line-wise visual selection.
  • Ctrl-v: Block-wise visual selection.

7. Troubleshooting

• “E325: ATTENTION”: Swap file exists. Usually means vim crashed or was improperly closed. Options:
  • (O)pen Read-Only: View the file without making changes.
  • (E)dit anyway: Edit the file anyway (may cause data loss if another instance is editing).
  • (R)ecover: Attempt to recover the file from the swap file.
  • (D)elete it: Delete the swap file.
  • (Q)uit: Quit.
  • (A)bort: Abort.
• Escaping Insert Mode: Press Esc to return to Normal mode.

8. Related Commands

• vi: The original Vi editor (often a symlink to vim).
• gvim: GUI version of vim.
• diff: Compare files.

B. nano

1. Command Overview

• What: A simple, easy-to-use text editor, especially suitable for beginners.
• When: Quickly editing configuration files, writing short scripts, basic text editing tasks.

2. Basic Syntax

nano [options] [file...]

3. Practical Examples

• Open a file:

  nano my_file.txt

• Create a new file:

  nano new_file.txt

4. Common Options

• -w: Disable word wrap.
• -m: Enable mouse support.
• -R: Read-only mode.
• -l: Display line numbers.
• -t num: Set tab size to num columns.
• -B: Enable taking backups of files.

5. Advanced Usage

• Using .nanorc: Customize nano’s behavior by editing ~/.nanorc. Example:

  set tabsize 4
  set tabstospaces
  set linenumbers
  set backup

• Search and Replace: Ctrl+\ to initiate the replace operation.
• Cut and Paste: Ctrl+K to cut a line, Ctrl+U to paste.

6. Tips & Tricks

• Keybindings: Displayed at the bottom of the screen. ^ represents Ctrl.
  • Ctrl+G: Get Help.
  • Ctrl+O: Write Out (save).
  • Ctrl+X: Exit.
  • Ctrl+R: Read File (insert file content).
  • Ctrl+W: Where Is (search).
  • Ctrl+\: Replace.
  • Ctrl+K: Cut Text.
  • Ctrl+U: Uncut Text (paste).
  • Ctrl+J: Justify (format paragraph).
  • Ctrl+T: To Spell (spell check).
  • Ctrl+C: Show cursor position.

7. Troubleshooting

• Permissions Issues: Make sure you have write permissions to the file.
• Terminal Size: Nano works best in a terminal with sufficient width and height.

8. Related Commands

• pico: Older, similar editor. Often a symlink to nano.

C. emacs

1. Command Overview

• What: A highly extensible, customizable text editor with a vast ecosystem of extensions and features. More than just a text editor; it’s a complete environment.
• When: Software development, writing documents, managing projects, email, and much more. Requires more initial learning but can be extremely powerful.

2. Basic Syntax

emacs [options] [file...]

3. Practical Examples

• Open a file:

  emacs my_file.txt

• Create a new file:

  emacs new_file.txt

• Open multiple files:

  emacs file1.txt file2.txt

4. Common Options

• -nw: Run in terminal mode (no GUI).
• -q: Start Emacs without loading the init file (~/.emacs or ~/.emacs.d/init.el).
• -u user: Load the init file for user.
• --daemon: Start Emacs as a daemon process in the background.
• --eval expr: Evaluate a Lisp expression.

5. Advanced Usage

• Using .emacs.d/init.el: Customize Emacs using Emacs Lisp. Example:

  (setq inhibit-startup-message t) ; Disable startup message
  (global-linum-mode 1) ; Enable line numbers globally
  (setq tab-width 4) ; Set tab width
  (setq indent-tabs-mode nil) ; Use spaces instead of tabs
  (global-auto-revert-mode 1) ; Automatically refresh buffers when files change

• Packages: Extend Emacs with packages from repositories like MELPA. Use M-x package-install (where M-x means Alt+x on most systems) to install packages. Example: M-x package-install solarized-theme.
• Buffers and Windows:
  • C-x C-f: Find file (open a file in a buffer).
  • C-x C-s: Save buffer.
  • C-x C-b: List buffers.
  • C-x k: Kill buffer.
  • C-x 2: Split window horizontally.
  • C-x 3: Split window vertically.
  • C-x o: Switch to another window.
  • C-x 0: Close current window.
  • C-x 1: Close all other windows.

6. Tips & Tricks

• Keybindings: Emacs uses Ctrl (C) and Alt (M) as modifier keys.
  • C-g: Cancel current command.
  • C-h: Help.
  • C-x C-c: Quit Emacs.
  • C-x C-f: Find File (open).
  • C-x C-s: Save File.
  • C-x s: Save all buffers.
  • C-s: Search forward.
  • C-r: Search backward.
  • M-%: Query Replace.
  • C-k: Kill (cut) to end of line.
  • C-y: Yank (paste).
  • M-w: Copy.
  • C-w: Cut.
  • C-a: Go to beginning of line.
  • C-e: Go to end of line.
  • M-<: Go to beginning of file.
  • M->: Go to end of file.
  • C-v: Scroll forward.
  • M-v: Scroll backward.
• Customization: Learn Emacs Lisp to deeply customize the editor.

7. Troubleshooting

• Keybinding Conflicts: Many keybindings are already defined. Use C-h k followed by the key combination to find out what it does.
• Init File Errors: Errors in ~/.emacs.d/init.el can prevent Emacs from starting. Start with emacs -q to bypass the init file and diagnose the problem.
• Learning Curve: Emacs has a steep learning curve. Start with the Emacs tutorial (C-h t).

8. Related Commands

• xemacs: A variant of Emacs with some different features.

II. Intermediate Linux Commands

A. Process Management

1. Command Overview

• What: Commands for monitoring, controlling, and managing processes running on the system.
• When: Troubleshooting performance issues, killing runaway processes, managing background tasks.

2. Basic Syntax

• ps [options]
• top [options]
• kill [options] PID
• killall [options] process_name
• bg [job_id]
• fg [job_id]
• jobs [options]
• nohup command [arguments] &
• systemctl [options] command service_name

3. Practical Examples

• List all running processes:

  ps aux

  USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
  root         1  0.0  0.0 168304  4944 ?        Ss   May01   0:05 /sbin/init
  root         2  0.0  0.0      0     0 ?        S    May01   0:00 [kthreadd]
  ...

• Find the process ID (PID) of a specific process:

  ps aux | grep my_process

• Kill a process by PID:

  kill 1234  # Sends SIGTERM (termination signal)

• Forcefully kill a process by PID:

  kill -9 1234  # Sends SIGKILL (immediate termination) - use with caution!

• Kill all processes with a specific name:

  killall my_process

• Start a process in the background:

  long_running_command &

• Bring a background process to the foreground:

  fg %1  # Bring job 1 to the foreground

• List all background jobs:

  jobs

  [1]+  Running                 long_running_command &

• Run a command that persists even after you close the terminal:

  nohup long_running_command > output.log 2>&1 &

• Start, stop, and restart services using systemctl (systemd):

  sudo systemctl start nginx
  sudo systemctl stop nginx
  sudo systemctl restart nginx
  sudo systemctl status nginx
  sudo systemctl enable nginx  # Start on boot
  sudo systemctl disable nginx # Disable on boot

4. Common Options

• ps:
  • aux: List all processes with detailed information (user, PID, CPU usage, memory usage, etc.).
  • ef: Similar to aux, but with a different format.
  • -u user: List processes owned by user.
• top:
  • -u user: Show processes owned by user.
  • -p PID: Monitor a specific process by PID.
  • q: Quit top.
  • h: Show help.
• kill:
  • -signal_number: Send a specific signal (e.g., -9 for SIGKILL, -15 for SIGTERM). kill -l lists signal names and numbers.
• killall:
  • -u user: Kill processes owned by user.
  • -e: Exact match for process name.
• jobs:
  • -l: List process IDs in addition to job information.
• nohup:
  • >: Redirect standard output.
  • 2>&1: Redirect standard error to standard output.
• systemctl:
  • status: Check the status of a service.
  • start: Start a service.
  • stop: Stop a service.
  • restart: Restart a service.
  • reload: Reload the configuration of a service without restarting.
  • enable: Enable a service to start on boot.
  • disable: Disable a service from starting on boot.
  • is-enabled: Check if a service is enabled to start on boot.
  • list-units: List all systemd units.

5. Advanced Usage

• Monitoring a process and restarting it if it crashes (using while loop):

  while true; do
    ./my_process
    echo "Process crashed, restarting..."
    sleep 5
  done

• Finding the process consuming the most CPU:

  ps aux --sort=-%cpu | head -n 10

• Finding the process consuming the most memory:

  ps aux --sort=-%mem | head -n 10

• Using renice to change the priority of a running process:

  renice -n 10 -p 1234 # Increase the priority (lower nice value) of process 1234
  renice -n 19 -p 1234 # Decrease the priority (higher nice value) of process 1234

  Note: Requires root privileges to decrease the nice value (increase priority).
• Creating custom systemd service files: Place service files in /etc/systemd/system/. Example:

  [Unit]
  Description=My Custom Service
  After=network.target
  
  [Service]
  User=myuser
  WorkingDirectory=/home/myuser/my_app
  ExecStart=/home/myuser/my_app/start.sh
  Restart=on-failure
  
  [Install]
  WantedBy=multi-user.target

  Then, run sudo systemctl daemon-reload to load the new service file.

6. Tips & Tricks

• Use pgrep to find PIDs by name: pgrep my_process
• Combine pgrep and kill: kill $(pgrep my_process)
• Use htop for an interactive process viewer (requires installation): sudo apt install htop (Debian/Ubuntu) or sudo yum install htop (CentOS/RHEL).
• Be careful when using kill -9. It doesn’t allow the process to clean up or save state, which can lead to data corruption. Try kill (SIGTERM) first.
• Use screen or tmux for persistent terminal sessions. These allow you to detach and reattach to a terminal session, so your processes continue running even if you close your terminal.

7. Troubleshooting

• “Operation not permitted”: You don’t have sufficient privileges to kill a process. Use sudo.
• Process doesn’t die after kill: The process might be ignoring the signal. Try kill -9 as a last resort.
• Service fails to start: Check the systemd journal for errors: sudo journalctl -u my_service.service

8. Related Commands

• nice: Run a command with a specified priority.
• renice: Change the priority of a running process.
• screen, tmux: Terminal multiplexers.
• systemd-analyze: Analyze systemd boot performance.
• journalctl: View systemd logs.

B. File System Management

1. Command Overview

• What: Commands for navigating, creating, modifying, and managing files and directories.
• When: Organizing files, managing storage space, setting permissions, automating file operations.

2. Basic Syntax

• cd [directory]
• pwd
• ls [options] [file...]
• mkdir [options] directory...
• rm [options] file...
• rmdir [options] directory...
• cp [options] source destination
• mv [options] source destination
• touch [options] file...
• chmod [options] file...
• chown [options] user:group file...
• df [options]
• du [options] [file...]
• find [path] [expression]
• tar [options] [file...]

3. Practical Examples

• Change directory:

  cd /var/log
  cd ..  # Go up one level
  cd ~   # Go to home directory
  cd -   # Go to the previous directory

• Print working directory:

  pwd

• List files and directories:

  ls -l  # Long listing format
  ls -a  # Show hidden files
  ls -t  # Sort by modification time
  ls -lh # Human readable file sizes

• Create a directory:

  mkdir my_directory
  mkdir -p /path/to/nested/directory # Create parent directories if they don't exist

• Remove a file:

  rm my_file.txt

• Remove a directory (must be empty):

  rmdir my_directory

• Remove a directory and its contents (use with extreme caution!):

  rm -rf my_directory  # -r: recursive, -f: force (no prompts)

• Copy a file:

  cp file1.txt file2.txt # Copy file1.txt to file2.txt
  cp -r directory1 directory2 # Copy directory1 to directory2 recursively

• Move/rename a file or directory:

  mv file1.txt file2.txt # Rename file1.txt to file2.txt
  mv file1.txt /path/to/destination/ # Move file1.txt to the destination directory

• Create an empty file or update the timestamp of an existing file:

  touch my_file.txt

• Change file permissions:

  chmod 755 my_script.sh  # Set permissions to rwxr-xr-x
  chmod +x my_script.sh  # Make the script executable
  chmod -R 777 /path/to/directory # recursively apply permissions (use with caution)

• Change file ownership:

  sudo chown user:group my_file.txt
  sudo chown -R user:group /path/to/directory # Recursively change ownership

• Check disk space usage:

  df -h  # Human-readable output
  df -i  # Show inode usage

• Check directory size:

  du -sh my_directory  # Human-readable summary
  du -h --max-depth=1 my_directory # Show sizes of subdirectories in my_directory

• Find files:

  find . -name "*.txt"  # Find all .txt files in the current directory and its subdirectories
  find /var/log -type f -mtime -7 # Find files in /var/log modified in the last 7 days
  find . -size +10M  # Find files larger than 10MB
  find . -user myuser # Find files owned by myuser
  find . -perm 755 # Find files with permission 755

• Create a tar archive:

  tar -cvf archive.tar file1.txt file2.txt directory1 # Create a tar archive
  tar -czvf archive.tar.gz file1.txt file2.txt directory1 # Create a gzipped tar archive
  tar -xvf archive.tar # Extract a tar archive
  tar -xzvf archive.tar.gz # Extract a gzipped tar archive
  tar -tvf archive.tar # List the contents of a tar archive

4. Common Options

• ls:
  • -l: Long listing format.
  • -a: Show all files, including hidden files (starting with .).
  • -t: Sort by modification time (newest first).
  • -r: Reverse the order of sorting.
  • -h: Human-readable file sizes (e.g., 1K, 234M, 2G).
  • -S: Sort by file size.
• mkdir:
  • -p: Create parent directories as needed.
• rm:
  • -r: Recursive (remove directories and their contents).
  • -f: Force (remove without prompting).
  • -i: Interactive (prompt before each deletion).
• cp:
  • -r: Recursive (copy directories and their contents).
  • -i: Interactive (prompt before overwriting).
  • -a: Archive (preserve permissions, ownership, and timestamps).
• mv:
  • -i: Interactive (prompt before overwriting).
• chmod:
  • [ugo][+-=][rwx] (e.g., chmod u+x file.txt - add execute permission for the owner). u (user), g (group), o (others), a (all).
  • [0-7][0-7][0-7] (e.g., chmod 755 file.txt). Octal representation of permissions.
  • -R: Recursive.
• chown:
  • -R: Recursive.
• df:
  • -h: Human-readable output.
  • -i: Show inode usage.
• du:
  • -s: Summary (show only the total size).
  • -h: Human-readable output.
  • --max-depth=n: Limit the depth of recursion.
• find:
  • -name pattern: Find files with a specific name pattern.
  • -type f: Find files.
  • -type d: Find directories.
  • -size [+-]size: Find files of a specific size. + for greater than, - for less than.
  • -mtime [+-]days: Find files modified within a certain number of days.
  • -user user: Find files owned by a specific user.
  • -exec command {} \;: Execute a command on each found file. {} is replaced with the filename. \; terminates the command.
  • -ok command {} \;: Like -exec, but prompts for confirmation before executing the command.
• tar:
  • -c: Create an archive.
  • -x: Extract an archive.
  • -v: Verbose (list files being processed).
  • -f file: Specify the archive filename.
  • -z: Compress with gzip.
  • -j: Compress with bzip2.
  • -t: List the contents of an archive.
  • -C directory: Change to directory before extracting.

5. Advanced Usage

• Finding and deleting files older than 30 days:

  find /path/to/directory -type f -mtime +30 -delete

  Important: Test this with -ls before using -delete to ensure you’re deleting the correct files.

  find /path/to/directory -type f -mtime +30 -ls

• Finding files and changing their permissions:

  find /path/to/directory -type f -name "*.txt" -exec chmod 644 {} \;

• Creating a tar archive excluding certain files or directories:

  tar -czvf archive.tar.gz --exclude='./exclude_directory' --exclude='*.log' ./my_directory

• Using rsync for efficient file synchronization (more advanced, but very useful):

  rsync -avz /source/directory/ /destination/directory/
  rsync -avz user@remote_host:/source/directory/ /destination/directory/

• Creating a hard link and a symbolic link:

  ln file1.txt hardlink.txt # Create a hard link
  ln -s file1.txt symlink.txt # Create a symbolic link

6. Tips & Tricks

• Use tab completion to speed up typing file and directory names.
• Use !! to repeat the last command.
• Use sudo !! to run the last command with root privileges.
• Use wildcards (*, ?, []) to select multiple files.
  • *.txt: All files ending in .txt.
  • file?.txt: Files like file1.txt, file2.txt, etc.
  • file[1-5].txt: Files like file1.txt, file2.txt, …, file5.txt.
• Use xargs to pass a large number of filenames to a command:

  find . -name "*.txt" | xargs rm # Remove all .txt files

• Be extremely careful when using rm -rf. Double-check the path before running it.

7. Troubleshooting

• “Permission denied”: You don’t have the necessary permissions to access or modify the file or directory. Use sudo or change the permissions with chmod.
• “No such file or directory”: The file or directory you’re trying to access doesn’t exist. Double-check the path.
• “Disk quota exceeded”: You’ve exceeded your disk quota. Delete unnecessary files or request a quota increase.
• “File exists”: The file you’re trying to copy or move already exists. Use the -i option to prompt before overwriting.

8. Related Commands

• ln: Create hard links and symbolic links.
• rsync: Synchronize files and directories.
• mount, umount: Mount and unmount file systems.
• fdisk, parted: Partition management tools (use with extreme caution!).
• mkfs: Create a file system.

C. Networking

1. Command Overview

• What: Commands for configuring, troubleshooting, and monitoring network connections.
• When: Diagnosing network issues, configuring network interfaces, testing connectivity, monitoring network traffic.

2. Basic Syntax

• ip [options] address
• ifconfig [interface] [options] (Deprecated, but still commonly used)
• ping [options] destination
• traceroute [options] destination
• netstat [options] (Deprecated, replaced by ss)
• ss [options]
• nslookup [domain]
• dig [options] domain
• curl [options] URL
• wget [options] URL
• ssh [options] user@host
• scp [options] user@host:file local_file
• tcpdump [options] [expression]

3. Practical Examples

• Show network interface configuration (using ip):

  ip addr show

• Show network interface configuration (using ifconfig - deprecated):

  ifconfig eth0

• Ping a host:

  ping google.com

• Trace the route to a host:

  traceroute google.com

• List listening ports (using ss):

  ss -tulnp

• List listening ports (using netstat - deprecated):

  netstat -tulnp

• Look up the IP address of a domain (using nslookup):

  nslookup google.com

• Look up DNS records (using dig):

  dig google.com
  dig MX google.com # Check mail exchange records

• Download a file using curl:

  curl -O https://example.com/file.txt # Save file to current directory
  curl -o my_file.txt https://example.com/file.txt # Save file to my_file.txt

• Download a file using wget:

  wget https://example.com/file.txt

• Connect to a remote host using SSH:

  ssh user@remote_host
  ssh -p 2222 user@remote_host # Connect to port 2222
  ssh -i ~/.ssh/my_private_key user@remote_host # Use a specific private key

• Copy a file to a remote host using SCP:

  scp my_file.txt user@remote_host:/path/to/destination/

• Capture network traffic (using tcpdump - requires root):

  sudo tcpdump -i eth0 -n -vv port 80 # Capture HTTP traffic on eth0
  sudo tcpdump -i any -n -vv icmp # Capture ICMP traffic on all interfaces

4. Common Options

• ip:
  • addr show: Show network interface addresses.
  • `