A Developer's Guide to Essential Terminal Commands

This guide provides a curated list of essential commands for Git, the GitHub CLI, and your Terminal. Each command includes a breakdown of its arguments to help you understand what's happening and how to use them effectively in your daily workflow.

🐙 Git Commands

1. Everyday Workflow & Inspection

• Check Status: Get a compact, single-line overview of your repository's status.

  Bash

    git status -s
  

  • -s or --short: Provides output in a short, easy-to-read format. M means modified, A means added, ?? means untracked, etc.

• Power Log: View a condensed, graph-based log of all commits across all branches.

  Bash

    git log --oneline --graph --decorate --all
  

  • --oneline: Condenses each commit to a single line (hash and commit message).

  • --graph: Draws a text-based graph showing the branch structure.

  • --decorate: Shows branch names, tags, and other references pointing to commits.

  • --all: Displays commits from all branches, not just the current one.

• View Unstaged Changes: See the differences between your working directory and the last commit (what you could stage).

  Bash

    git diff
  

• View Staged Changes: See the differences between your staged changes and the last commit (what you are about to commit).

  Bash

    git diff --staged
  

  • --staged or --cached: Shows changes that have been added to the index via git add.

• Interactive Staging: Interactively review and stage portions (or "hunks") of code from your modified files instead of staging the entire file.

  Bash

    git add -p
  

  • -p or --patch: Enters an interactive mode where Git shows you each change and asks if you want to stage it (y), skip it (n), split it into smaller changes (s), etc.

• Verbose Commit: Open your text editor to write a commit message, but also include the full diff of your changes in the editor as a comment for context.

  Bash

    git commit -v
  

  • -v or --verbose: Helps you write more accurate commit messages by showing you exactly what you've changed.

2. Branching & History Manipulation

• Switch Branches: The modern, intuitive command to switch between existing branches.

  Bash

    git switch <branch-name>
  

• Create and Switch to a New Branch: A single command to create a new branch from your current position and immediately switch to it.

  Bash

    git switch -c <new-branch-name>
  

  • -c or --create: The flag that tells Git to create a new branch.

• Interactive Rebase: The ultimate tool for cleaning up commit history. It opens an editor allowing you to reorder, squash (combine), edit, or remove recent commits before merging.

  Bash

    git rebase -i main
  

  • -i or --interactive: Enters the interactive mode.

  • main: The target branch. This command rewrites the history of your current branch on top of main.

• Cherry Pick: Apply a specific commit from another branch to your current branch.

  Bash

    git cherry-pick <commit-hash>
  

  • <commit-hash>: The unique identifier of the commit you want to copy over.

• Hard Reset: DANGER! Discards your last commit and all the changes in your working directory associated with it. Use with extreme caution.

  Bash

    git reset --hard HEAD~1
  

  • --hard: Resets the commit history, the staging area, AND your working directory.

  • HEAD~1: Refers to the commit just before the current one (HEAD).

• Soft Reset: Undoes the last commit but keeps all the changes from that commit in your staging area, ready to be re-committed.

  Bash

    git reset --soft HEAD~1
  

  • --soft: Resets the commit history only, leaving your files and staging area untouched.

• Reflog: Your safety net. It shows a log of every movement HEAD has made. If you ever mess up a rebase or reset, reflog is how you can find your "lost" commits and restore them.

  Bash

    git reflog
  

3. Working with Remotes

• Fetch: Download all the latest changes (commits, branches, tags) from the remote repository but does not merge them into your local branches.

  Bash

    git fetch
  

• Pull with Rebase: The recommended way to update your local branch. It fetches remote changes and then "re-plays" your local commits on top of the latest remote version, maintaining a clean, linear history.

  Bash

    git pull --rebase
  

• Force Push with Lease: A safer way to force push. It will fail if someone else has pushed new commits to the remote branch since you last fetched, preventing you from accidentally overwriting their work.

  Bash

    git push --force-with-lease
  

• Push and Set Upstream: Push a new local branch to the remote and configure it to track the remote branch. This lets you use git pull and git push without extra arguments in the future.

  Bash

    git push -u origin <branch-name>
  

  • -u or --set-upstream: Creates the tracking connection between your local branch and the new remote branch.

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🚀 GitHub CLI (gh): Your Superpower

The GitHub CLI brings GitHub to your terminal, saving you from switching to the browser.

1. The Pull Request Workflow

• Create a PR: Interactively create a pull request from your current branch. gh will prompt you for the title, body, reviewers, and more.

  Bash

    gh pr create
    # Or with flags:
    gh pr create --title "My PR Title" --body "Details here" --reviewer "username"
  

• List PRs: See a list of open pull requests in the repository.

  Bash

    gh pr list
  

• Checkout a PR: Download the code from a specific pull request into a new local branch so you can test it.

  Bash

    gh pr checkout <pr-number>
  

• View PR Diff: See the file changes for a specific PR directly in your terminal.

  Bash

    gh pr diff <pr-number>
  

• Review a PR: Start an interactive session to approve, comment on, or request changes for a pull request.

  Bash

    gh pr review <pr-number>
  

• Merge a PR: Merge a pull request from the command line.

  Bash

    gh pr merge <pr-number> --squash --delete-branch
  

  • --squash: Combines all commits in the PR into a single commit on the base branch.

  • --delete-branch: Deletes the remote branch after merging.

2. Other Handy gh Commands

• Clone a Repo: A simpler way to clone a repository you have access to.

  Bash

    gh repo clone <owner/repo>
  

• View Repo in Web: Quickly open the current repository's GitHub page in your default web browser.

  Bash

    gh repo view -w
  

  • -w or --web: Specifies opening in the web browser.

• List Issues: View and filter the project's issues.

  Bash

    gh issue list
  

• List Action Runs: Check the status of your GitHub Actions CI/CD runs.

  Bash

    gh run list
  

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💻 Terminal Commands (Linux/macOS)

1. Navigation & Directory Management

• ls – List Files: Lists files and directories.

  Bash

    ls -lh
  

  • -l: Long listing format (shows permissions, owner, size, date).

  • -h: Human-readable sizes (e.g., 4.0K, 1.2M).

  • -a: Shows all files, including hidden dotfiles (e.g., .bashrc).

  • -t: Sorts by modification time, newest first.

  • -R: Recursively lists subdirectories.

• tree – Display Directory Structure: Visualizes the folder hierarchy as a tree. (May need to be installed: sudo apt install tree or brew install tree).

  Bash

    tree -L 2
  

  • -L 2: Limits the depth of the tree to 2 levels.

• find – Search for Files: A powerful tool to locate files.

  Bash

    find . -name "*.java"
  

  • .: The path to search in (current directory).

  • -name "*.java": The expression to match (any file ending in .java).

  • -type f: Find only files.

  • -type d: Find only directories.

  • -mtime -1: Find files modified in the last 24 hours.

2. File Viewing & Manipulation

• cat – View File Contents: Prints the entire content of a file to the screen.

  Bash

    cat file.txt
  

• less – Paginated File Viewer: View large files page by page. Use arrow keys to navigate and q to quit. Much better than cat for large log files.

  Bash

    less app.log
  

• head and tail: Preview the beginning or end of a file.

  Bash

    tail -n 50 app.log
    tail -f app.log
  

  • -n 50: Shows the last 50 lines.

  • -f: "Follow" mode. Continuously outputs new lines as they are added to the file, great for watching live logs.

• grep – Search Within Files: Find lines containing a specific pattern.

  Bash

    grep -r "LinkedInService" src/
  

  • -r or -R: Recursive search through a directory.

  • -i: Case-insensitive search.

  • -v: Invert match; shows lines that do not contain the pattern.

  • --line-buffered: Useful when piping from a command like tail -f.

3. System & Process Management

• ps – Process Status: List currently running processes. Often used with grep to find a specific one.

  Bash

    ps aux | grep java
  

  • aux: A common set of flags to show all processes (a), including those without a terminal (x), with user details (u).

• kill – Terminate a Process: Send a signal to a process (identified by its PID) to terminate it.

  Bash

    kill 12345
    kill -9 12345
  

  • By default, kill sends a TERM signal, asking the process to shut down gracefully.

  • -9: Sends the KILL signal, which is non-blockable and forces the process to terminate immediately. Use this as a last resort.

• df – Disk Usage: Report file system disk space usage.

  Bash

    df -h
  

  • -h: Human-readable format (e.g., GB, MB).

• du – Directory Size: Show the disk usage of files and directories.

  Bash

    du -sh *
  

  • -s: Summarize, showing a total for each argument.

  • -h: Human-readable format.

4. Networking

• ss – Socket Statistics: A modern replacement for netstat that displays network connection information.

  Bash

    ss -tulpn
  

  • -t: Show TCP sockets.

  • -u: Show UDP sockets.

  • -l: Show only listening sockets.

  • -p: Show the process using the socket.

  • -n: Do not resolve service names (show port numbers).

• lsof – List Open Files: A powerful debugging tool to see which process is using a specific file or port.

  Bash

    lsof -i :8080
  

  • -i :8080: Shows the process listening on port 8080.

5. Shell Power-Ups

• Piping |: Use the output of one command as the input for another.

  Bash

    # Find all Java processes, then count them
    ps aux | grep java | wc -l
  

• Redirection > & >>: Send the output of a command to a file.

  Bash

    # Overwrite files.txt with the list of files
    ls -l > files.txt 
  
    # Append the list of files to files.txt
    ls -l >> files.txt
  

• xargs – Execute Arguments: Takes items from standard input and passes them as arguments to another command.

  Bash

    # Find all .tmp files and delete them
    find . -name "*.tmp" | xargs rm
  

• tee – Split Output: Reads from standard input and writes to both standard output and one or more files simultaneously.

  Bash

    # Run the deploy script, see the output on screen, AND save it to deploy.log
    ./deploy.sh | tee deploy.log