Shell debian reduce image size bigger than especific width - image

Someone knows ifbthere are some option in shell look formimages bigger than a size and reduce them to a maximum size.

Sure, use ImageMagick. Make a backup first and try on a copy of a few images as this resizes irretrievably!
find . -iname \*.jpg -exec mogrify -resize 640x480\> {} \;
Examples

Related

Convert 5 Mio tiff Files in png

i am thinking about the best and fastet way to convert 5 Mio tiff Files (in Folders Subfolders and SubSubfolders) in 5 Mio png Files (same directory).
Is there any way to parallelise this job?
How could i check then if all files are converted?
ls *.tif | wc -l # compared to
ls *.png | wc -l
but for every folder.
Thanks.
Marco
Your question is very vague on details, but you can use GNU Parallel and ImageMagick like this:
find STARTDIRECTORY -iname "*.tif" -print0 | parallel -0 --dry-run magick {} {.}.png
If that looks correct, I would make a copy of a few files in a temporary location and try it for real by removing the --dry-run. If it works ok, you can add --bar for a progress bar too.
In general, GNU Parallel will keep N jobs running, where N is the number of CPU cores you have. You can change this with -j parameter.
You can set up GNU Parallel to halt on fail, or on success, or a number of failures, or after currently running jobs complete and so on. In general you will get an error message if any file fails to convert but your jobs will continue till completeion. Run man parallel and search for --halt option.
Note that the above starts a new ImageMagick process for each image which is not the most efficient although it will be pretty fast on a decent machine with good CPU, disk subsystem and RAM. You could consider using different tools such as vips if you feel like experimenting - there are a few ideas and benchmarks here.
Depending on how your files are actually laid out, you might do better using ImageMagick's mogrify command, and getting GNU Parallel to pass as many files to each invocation as your maximum command line length permits. So, for example, if you had a whole directory of TIFFs that you wanted to make into PNGs, you can do that with a single mogrify like this:
magick mogrify -format PNG *.tif
You could pair that command with a find looking for directories something like this:
find STARTDIRECTORY -type d -print0 | parallel -0 'cd {} && magick mogrify -format PNG *.tif`
Or you could find TIFF files and pass as many as possible to each mogrify something like this:
find STARTDIRECTORY -iname "*.tif" -print0 | parallel -0 -X magick mogrify -format PNG {}

Bash: find files within file size range and report their names to a file

I would like to write a Bash script that selects files within a given folder with file size between 10kB and 100kB. This list of files should be written to a new file. Something like:
fileSelector ~/my-folder-containing-files ~/my-report-file
Can you help me develop such a script using bash?
If you just want to get a list of files within a specific size range, you can try:
$ find . -type f -size +10k -size -101k -exec ls {} \;
notice that since the size is calculated to be rounded up to the next unit, you would actually get a size range between 10241 to 102400 bytes from the above expression
if you want to make the limits to be byte-precise, you can use:
$ find . -type f -size +10239c -size -102401c -exec ls {} \;

How to check the size of all files inside a directory and empty it if it is exceeding certain size

I am a bit new to the bash scripting and have a scenario on which i need to know the efficient way to complete.
I need to check the size of all the files inside a directory and if the size of any files exceeds certain limit i need to empty those files and then send email to a mail ID with details like name of the files which are emptied, the original size, the current size after emptying.
Found lots of blog on the same topic but just wanted to check the most efficient way i can complete the above scenario.
Thanks
Was able complete the above scenario with the help of find command.
rm -f logFile*
find . -type f -size +20k -exec du -sh {} \; >> logFile.txt
cat logFile*
find . -type f -size +20k -exec truncate -s 0 {} \;

Simple way to resize large number of image files

I have a folder which contains about 45000 jpeg images. Most of them are from 10KB - 20Kb.
Now I want to write a script to resize all of them to fixed size 256x256. I wonder if there is any simple way to do that like: for a in *.jpg do .... I am using 8-core CPU with 8GB of RAM machine running Ubuntu 14.04, so it is fine if the process requires many resources
I would use GNU Parallel, like this to make the most of all those cores:
find . -name \*.jpg | parallel -j 16 convert {} -resize 256x256 {}
If you had fewer files, you could do it like this, but the commandline would be too long for 45,000 files:
parallel -j 16 convert {} -resize 256x256 {} ::: *.jpg
Also, note that if you want the files to become EXACTLY 256x256 regardless of input dimensions and aspect ratio, you must add ! after the -resize like this -resize 256x256!
As Tom says, make a backup first!
Here is a little benchmark...
# Create 1,000 files of noisy junk #1024x1024 pixels
seq 1 1000 | parallel convert -size 1024x1024 xc:gray +noise random {}.jpg
# Resize all 1,000 files using mogrify
time mogrify -resize 256x256 *.jpg
real 1m23.324s
# Create all 1,000 input files afresh
seq 1 1000 | parallel convert -size 1024x1024 xc:gray +noise random {}.jpg
# Resize all 1,000 files using GNU Parallel
time parallel convert -resize 256x256 {} {} ::: *.jpg
real 0m22.541s
You can see that GNU Parallel is considerably faster for this example. To be fair though, it is also wasteful of resources though because a new process has to be created for each input file, whereas mogrify just uses one process that does all the files. If you knew that the files were named in a particular fashion, you may be able to optimise things better...
Finally, you may find xargs and mogrify in concert work well for you, like this:
time find . -name \*.jpg -print0 | xargs -0 -I {} -n 100 -P 8 mogrify -resize 256x256 {}
real 0m20.840s
which allows up to 8 mogrify processes to run in parallel (-P 8), and each one processes up to 100 input images (-n 100) thereby amortizing the cost of starting a process over a larger number of files.
You could use the mogrify tool provided by ImageMagick
mogrify -resize 256x256 *.jpg
This modifies all files in place, resizing them to 256x256px. Make sure to take a backup of your originals before using this command.

How to search and resize images with dimensions higher than ... in Unix cli

How can i find and resize images with resolution higher that X width in unix cli?
I have tried
find -name *.jpg -exec mogrify -resize 800x800 -format jpg {} \;
but the problem is that resizes also the images that have width or height below from 800 pixels.
I have found it. This is it:
find * -iname '*.jpg' -print0 | xargs -0 mogrify -resize 800x800\> -monitor -format jpg

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