Automate Screenshots on Mac with the Command Line

In this guide, you will automate screenshots from Terminal with macOS screencapture. You will check permission, test one capture, build full-screen and fixed-area loops, add an optional page-turn keypress, then learn how to stop and troubleshoot the run.

Check permission before debugging the command

If a capture is blank or misses protected app content, Terminal may need screen capture access. Open System Settings > Privacy & Security > Screen & System Audio Recording, allow Terminal, then reopen Terminal if macOS asks.

You do not need Accessibility access for screenshots alone. It is required only when osascript controls another app or sends a key through System Events.

Take one screenshot from Terminal

Start with a single file:

screencapture -x "$HOME/Desktop/test-screenshot.png"

The -x option turns off the screenshot sound. If the file looks correct, move on to a short loop.

Useful built-in options include:

Option	Result
-R x,y,width,height	Capture a fixed rectangle
-m	Capture only the main monitor
-i	Choose an area or window interactively
-w	Allow interactive window selection only
-T 5	Delay a capture by five seconds
-t jpg	Save in JPG format
-C	Include the cursor in a non-interactive capture

The -T flag works as a simple screenshot timer. Run man screencapture in Terminal to see the options available on your version of macOS.

Capture the full screen every few seconds

Use this three-frame loop before a longer run:

RUN_DIR="$HOME/Desktop/screenshot-run-$(date +%Y%m%d-%H%M%S)"
mkdir -p "$RUN_DIR"
COUNT=3

for ((i=1; i<=COUNT; i++)); do
  screencapture -x "$RUN_DIR/frame-$(printf "%03d" "$i").png"
  if (( i < COUNT )); then
    sleep 5
  fi
done

The files sort as frame-001.png, frame-002.png, and so on. The conditional skips the unnecessary five-second wait after the final screenshot.

Check all three files before increasing COUNT for the real run. Press Control-C to stop early; files already saved remain in the run folder.

Capture one fixed area repeatedly

Add -R when the target stays in one place:

RUN_DIR="$HOME/Desktop/area-run-$(date +%Y%m%d-%H%M%S)"
mkdir -p "$RUN_DIR"
COUNT=20

for ((i=1; i<=COUNT; i++)); do
  screencapture -x -R 100,100,1200,800 "$RUN_DIR/frame-$(printf "%03d" "$i").png"
  if (( i < COUNT )); then
    sleep 5
  fi
done

The rectangle format is x,y,width,height. If the window moves, the command still captures the old coordinates. Run three frames first and move the target only after the loop finishes.

On Retina displays, a 400x300 logical rectangle may produce an 800x600 Retina screenshot. The command used the right area; macOS saved it at the display's pixel density.

Save JPG files instead of PNG

Use -t jpg and a .jpg extension:

screencapture -x -t jpg "$HOME/Desktop/test-screenshot.jpg"

PNG is a safer default for interface text and diagrams. JPG is smaller for photographic content but can soften small text.

Press a key between screenshots without overshooting

This page-turn loop captures first, presses the right arrow only when another capture remains, then waits for the new page to render:

RUN_DIR="$HOME/Desktop/page-run-$(date +%Y%m%d-%H%M%S)"
mkdir -p "$RUN_DIR"
COUNT=50

for ((i=1; i<=COUNT; i++)); do
  screencapture -x "$RUN_DIR/page-$(printf "%03d" "$i").png"

  if (( i < COUNT )); then
    osascript -e 'tell application "System Events" to key code 124'
    sleep 1
  fi
done

key code 124 is the right arrow. The if (( i < COUNT )) guard prevents another keypress after the final page has been captured.

Test with three pages first. Keep the target app in front for the whole run. If focus changes, System Events sends the arrow to the wrong app.

Keep a long run awake

For an unattended run, put the script in a file and launch it through caffeinate:

caffeinate -i /bin/zsh "$HOME/Desktop/capture-run.zsh"

The -i option prevents idle system sleep while the script is running. It does not fix a locked screen, a moved window, or an app that stopped updating, so test the workflow before leaving it alone.

Troubleshoot a failed screencapture loop

Symptom	What to check
Blank or incomplete image	Give Terminal Screen & System Audio Recording access, reopen it, and retest
could not create image from display	Confirm the session is logged in and the display is available
Wrong crop	Update the -R coordinates after placing the window in its final position
Files overwrite each other	Use a new timestamped folder and unique numbered names
Right arrow goes elsewhere	Restore focus to the target app and shorten the test to three pages
A page is skipped	Increase the sleep after the keypress
Script keeps running	Return to Terminal and press Control-C

When a script is no longer the easy option

Command-line screenshot automation is a good fit for stable coordinates, raw files, and workflows you are comfortable maintaining. When each run needs a different target, count, interval, keypress, or review step, a visual interface is easier to adjust.

Shotomatic keeps those capture controls and finished frames in one Mac app, with image, ZIP, PDF, and MP4 export. See how Shotomatic handles screenshot automation on Mac.

If the images already exist and the main task is packaging them, follow how to save screenshots as a PDF on Mac.

FAQ

Can I automate screenshots from Terminal on Mac?

Yes. Put the built-in screencapture command inside a shell loop and give every output file a unique name.

How do I stop a screencapture loop?

Press Control-C in the Terminal window that is running it. Completed files stay in the output folder.

Can screencapture save JPG or PDF files?

Yes. Use -t jpg or -t pdf and match the output file extension. PNG remains a good default for interface screenshots.

Can the script press a key between captures?

Yes. Use osascript with System Events. Send the key only when another capture remains, grant Accessibility access if required, and keep the target app focused.