Things people ask how to do on their computer.
Each one answered properly: the way by hand, the one-line way, and the thing that goes wrong. Every command was run before it was written down. Or skip all of it and ask Titan.
Nothing here yet for that — ask Titan instead.
Photos and images
- Convert HEIC photos to JPG
How do I convert HEIC photos to JPG?
- Convert PNG images to JPG
How do I convert a PNG to a JPG?
- Convert JPG images to PNG
How do I convert a JPG to a PNG?
- Check an image’s dimensions
How do I see the pixel size of an image?
- Resize a batch of images
How do I resize a lot of images at once?
- Rotate a batch of images
How do I rotate many photos at once?
- Crop an image
How do I crop a photo without an editing app?
- Take a screenshot
How do I take a screenshot of part of the screen?
- Change where screenshots are saved
How do I stop screenshots cluttering my Desktop?
- Screenshot an entire webpage
How do I take a screenshot of a whole webpage, not just what fits on screen?
- Compress a JPG
How do I make a JPG file smaller without changing its size on screen?
- Flip an image
How do I mirror an image or flip it upside down?
- Make an image black and white
How do I turn a photo black and white?
PDFs and documents
- Combine PDFs into one
How do I merge several PDFs into one file?
- Combine photos into one PDF
How do I put several images into a single PDF?
- Turn a PDF page into an image
How do I convert a PDF to a PNG or JPG?
- Make a PDF file smaller
How do I reduce the file size of a PDF?
- Count the pages in a PDF
How do I see how many pages a PDF has without opening it?
- Count the words in a document
How do I count the words in a Word document or text file?
- Convert a Word document to plain text
How do I get the text out of a .docx file?
- Merge several text files into one
How do I combine multiple text files into one file?
- Sign a PDF
How do I sign a PDF without printing it?
- Save anything as a PDF
How do I save a webpage or document as a PDF?
- Copy a file’s text to the clipboard
How do I copy the contents of a text file without opening it?
Video and audio
- Make a video smaller (720p)
How do I make a video file smaller to send it?
- Trim a video
How do I cut the start or end off a video?
- Convert a MOV video to MP4
How do I convert a .mov file to .mp4?
- Get the audio out of a video
How do I extract the audio from a video?
- Convert audio to M4A
How do I convert a WAV or AIFF file to a smaller audio file?
- Turn text into a spoken audio file
How do I convert text to speech and save it as an audio file?
- Record audio
How do I record my voice on my computer?
Lists and text
- Remove duplicate lines from a list
How do I remove duplicates from a list?
- Sort a list alphabetically
How do I sort a list of names alphabetically?
- Pull email addresses out of text
How do I extract all the email addresses from a document?
- Count the rows in a CSV file
How many rows are in my CSV file?
- Find and replace text in many files
How do I replace a word across many files at once?
Finding things
- Find the file you worked on yesterday
How do I find a file I was working on yesterday?
- Find a file by its name
How do I find a file when I only remember part of its name?
- Search inside files for a word
How do I find which file contains a certain word or phrase?
- Count the files in a folder
How do I see how many files are in a folder?
- Save a list of a folder’s contents
How do I export a list of files in a folder to a text file?
- Copy a file’s full path
How do I get the full path of a file?
Files and space
- Rename many files at once
How do I batch rename files?
- Zip a folder
How do I zip a folder to send it?
- Zip a folder with a password
How do I password-protect a zip file?
- Open (unzip) a zip file
How do I unzip a file?
- Find what is taking up disk space
How do I find large files taking up space?
- Find duplicate files
How do I find duplicate files taking up space?
- Clean up old files in Downloads
How do I delete old files from my Downloads folder?
- See how much storage is left
How much free space do I have on my computer?
- Show hidden files
How do I see hidden files and folders?
- See how big a folder is
How do I check the size of a folder?
- Copy a folder to a backup drive
How do I back up a folder, copying only what changed?
- Make a password-protected folder
How do I put files in an encrypted, password-protected container?
- Lock a file so it can’t be changed
How do I stop a file from being edited or deleted by mistake?
- Find empty folders
How do I find and delete empty folders?
- Rename files by date
How do I rename photos or files by the date they were taken?
- Sort files into folders by type
How do I sort a messy folder into folders by file type?
- Hide a file or folder
How do I hide a file or folder so it doesn’t show in Finder?
- Change a file’s date
How do I change the date on a file?
- Change the extension of many files
How do I rename .jpeg files to .jpg (or change any extension in bulk)?
- Open a .tar.gz file
How do I open or extract a .tar.gz file?
- Compare two files for differences
How do I see what changed between two versions of a file?
Your computer
- Find what is slowing your computer down
Why is my laptop or computer slow, and what is using the CPU?
- Check your laptop battery health
How do I check my laptop battery health and cycle count?
- Keep your computer from going to sleep
How do I stop my computer from sleeping during a download or presentation?
- Check which system version you have
What version of macOS do I have?
- See your computer’s chip and memory
How do I check what chip and how much memory my computer has?
- List every app you have installed
How do I see all the apps installed on my computer?
- Find which version of an app you have
How do I check the version of an app?
- Check your internet speed
How do I test my internet speed without a website?
- Find your IP address
How do I find my IP address?
- See the time in another city
What time is it in Tokyo (or any city) right now?
- Generate a strong password
How do I create a strong random password?
- Force quit a frozen app
How do I force quit an app that is not responding?
- See which apps are using the internet
How do I see which apps are using my network?
- Lock your screen
How do I lock my computer quickly?
- Type an emoji
How do I type emoji on my computer?
- Check if a website is down
Is a website down for everyone or just me?
- Download a file from a link in Terminal
How do I download a file with the command line?
- Check a download’s checksum
How do I verify the SHA-256 checksum of a downloaded file?
- Count the days until a date
How many days until a date?
- Check your disk’s health
How do I check if my SSD or hard drive is healthy?
- See which Wi-Fi network you are on
How do I see the name of the Wi-Fi network I’m connected to?
- See your screen resolution
What is my screen resolution?
- Turn a timestamp into a date
How do I convert a Unix timestamp to a readable date?
- See how long your computer has been on
How long has my computer been on since it last restarted?
For developers
- Find what is using a port
Port 3000 is already in use — what is using it?
- Free up a port that is in use
How do I stop whatever is using port 3000?
- Make a JSON file readable
How do I pretty-print a JSON file?
- Encode or decode Base64
How do I encode or decode Base64?
Making things
- Turn notes into a slide deck
How do I turn my notes into slides quickly?
- Make a simple 3D model for printing
How do I make an STL file for my 3D printer?