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I have a large set of JPEG pictures all with the same resolution. It would take too long to open each one inside the graphical interface of imagemagic or gimp.

How do I achieve each picture being rotated and saved as the same filename?

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3 Answers 3

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You can use the convert command:

convert input.jpg -rotate <angle in degrees> out.jpg

To rotate 90 degrees clockwise:

convert input.jpg -rotate 90 out.jpg

To save the file with the same name:

convert file.jpg -rotate 90 file.jpg

To rotate all files:

for photo in *.jpg ; do convert $photo -rotate 90 $photo ; done

Alternatively, you can also use the mogrify command line tools (the best tool) recommended by @don-crissti:

mogrify -rotate 90 *.jpg
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    thx, how do I tell the command that the filename left of -rotate -180 has to be the same as right of it , if there are many files?
    – sharkant
    May 17, 2017 at 11:42
  • Rotating a file 180 degrees will always give you the same result, no matter if you rotate it left or right.
    – djsmiley2kStaysInside
    May 17, 2017 at 14:17
  • @GAD3R 360 degrees will result in the same image afterwards. Rotating an image left or right by 180 degrees, with both give you the same image (but upside down).
    – djsmiley2kStaysInside
    May 17, 2017 at 14:21
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    $CAPITAL_NAMES should be left to environment variables; for those local variables in shell scripts or commands use $normal_lowercase
    – cat
    May 17, 2017 at 16:46
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    convert re-encodes JPEG and hence is lossy. Better use jpegtran
    – imz -- Ivan Zakharyaschev
    Aug 6, 2017 at 12:44
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For JPEG images and right-angle rotations, use jpegtran or exiftran, as they can rotate the images losslessly.

for f in *.jpg ; do 
    jpegtran -rotate 180 "$f" > "${f%.jpg}-rotated.jpg"
done

Or to rotate in-place:

for f in *.jpg ; do
    jpegtran -rotate 180 -outfile "$f" "$f"
done

exiftran also has the -a flag to automatically rotate the image based on what the EXIF orientation tag says.

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  • For counter-clockwise (left-angle) rotation with jpegtran, use -rotate 270 and with exiftran use -2flag according to the manual.
    – Timo
    Mar 12, 2018 at 19:47
  • *.jpg works under bash but under zshell it causes the error jpegtran: can't open *.jpg for reading but *jpg works for me in zshell.
    – Konrad Höffner
    Dec 28, 2020 at 10:09
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Note that the two other answers may provide different results depending on the EXIF Orientation : it seems that convert rotates with regards to the EXIF Orientation, while jpegtran just ignores the EXIF Orientation.

This observation led me to figure I actually needed to discard the EXIF Orientation, so I just used exiftool to discard EXIF data without further data loss (that's also what does jpegtran when no -rotate option is given, it seems) :

exiftool -all= -o outfile.jpg infile.jpg

I could have just removed the EXIF Orientation with

exiftool -Orientation= -o outfile.jpg infile.jpg

or modified it with

exiftool -n -Orientation=1 -o outfile.jpg infile.jpg

(for this later case you will need to read the FAQ to understand option -n, needed for exiftool to translate the -Orientation value, and the EXIF tags table).

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