Ubuntu – Find images in a Linux directory based on their resolution

bashcommand linefindimage processingsearch

I would like to scan all images in a directory (recursively within sub-folders), and find those with resolution higher than a specific threshold (e.g. say those with resolutions at least 800x600 or if easier, say with width higher than 1000 pixels). Then I would like to log their address in a text file, accompanying their resolution (or [width], [height] for a better formatting).

So log.txt would look like this:

/home/users/myuser/test/image1.jpg, 1800, 1600
/home/users/myuser/test/image20.jpg, 2800, 2600
/home/users/myuser/test/image30.jpg, 1500, 1200

How can I do that that using a bash script? I have to scan millions of images.

Best Answer

Via bash's recursive glob and ImageMagick's identify command:

shopt -s globstar
identify -format "%f, %w, %h\n" **/*.{png,jpg,jpeg}

Saving such output to file , is just a matter of adding > mylog.txt to previous command, that is

identify -format "%f, %w, %h\n" **/*.{png,jpg,jpeg} > mylog.txt

From there, you could use awk or perl to compare mylog.txt columns

awk -F ',' '$2 > 800 && $3 > 600' mylog.txt

awk here uses , as separator for columns, and the usual structure for awk is /PATTERN/{COMMANDS}, which defaults to just printing if {COMMANDS} omitted ; in the particular example above, if the pattern $2 > 800 && $3 > 600 is true, that is it's the image above desired resolution, you'll get it printed to the screen.

And probably skipping the log step in between, it would be a little better to just pipe everything:

shopt -s globstar
identify -format "%f, %w, %h\n" **/*.{png,jpg,jpeg} | awk -F ',' '$2 > 800 && $3 > 600' > filtered_images.txt

In case you encounter arguments list too long error, typically find command is better approach for recursively walking the directory tree. The identify can be called through find's -exec flag, and filtering still can be handled by awk:

$ find -type f -regex "^.*\.\(png\|jpg\|jpeg\)$" -exec identify -format "%f, %w, %h\n" {} \; | awk -F ',' '$2 > 800 && $3 > 600' 
fanart.jpg, 1920, 1080
fanart.jpg, 1920, 1080
globalsearch-background.jpg, 1920, 1080
fanart.jpg, 1280, 720

As usual, don't forget to add > log2.txt to save everything to file.

Full path of to the file could be handled in either one of two ways. One, by specifying %d/%f in identify command's format string, or use find's -printf option. That is either

find -type f -regex "^.*\.\(png\|jpg\|jpeg\)$" -exec identify -format "%d/%f, %w, %h\n" {} \; | awk -F ',' '$2 > 800 && $3 > 600'

find -type f -regex "^.*\.\(png\|jpg\|jpeg\)$" -printf "%p, " -exec identify -format "%w, %h\n" {} \; | awk -F ',' '$2 > 800 && $3 > 600'

Finding Files with `bat` Anywhere

To find all files anywhere inside /path/to/folder whose names contain bat, you can use:

find /path/to/folder -name '*bat*'

I have quoted the search pattern *bat* because, if the quotes were omitted and files match *bat* in the current directory, the shell will expand *bat* into a list of them and pass that to find. Then find wouldn't work right. (\*bat\* and "*bat*" also work.)

To search in the folder you're currently in (e.g., that you've cded to), use ., as usual:

find . -name '*bat*'

To search your whole computer, use /. To search your home directory, use ~, or the full name of your home directory. (The shell expands ~ to your home directory's fully qualified path.)

Broadening or Narrowing Your Search, Based on Name

If you want to search case-insensitively, so files containing BAT, bAt, and so forth are matched, use the -iname test instead of the -name test:

find /path/to/folder -iname '*bat*'

I've noticed all your files end in .c. If you only want to find files like that, use:

find /path/to/folder -name '*bat*.c'

I noticed all your filenames have bat either at the very beginning or the very end of the part preceding the .c suffix. If you want to avoid matching files like embattled.c, you could use:

find /path/to/folder -name '*bat.c' -o -name 'bat*.c'

-o is the or operator.

Matching Only Files

To find only regular files--and not folders, symbolic links, and special device nodes--you can use -type f. This is frequently recommended and sometimes quite appropriate... but often not what you really want, especially if you're running find for the purpose of examining the output yourself. If you had a symbolic link that matched your search, wouldn't you want to know about it?

If you want to find both regular files and symbolic links, you can use:

find /path/to/folder -name '*bat*' \( -type f -o -type l \)

That uses the -o operator and also parentheses for grouping (which must be quoted so the shell does not treat them specially; otherwise you'll get a syntax error).

But suppose you only want to see symbolic links that ultimately point to a regular file (and not symbolic links to directories, device nodes, etc.). That's actually even simpler: use -xtype instead of -type. Provided you're not running find with -L flag, -xtype on a symbolic link tests the type of the file the link points to.

find /path/to/folder -name '*bat*' -xtype f

If you have a symlink to another symlink to a file, -xtype f will match it even though its direct target is another symlink rather than a regular file. This is almost always what you want.

Often people think they want -type f, but really they want -xtype f.

Getting Detailed Output

find's default action if you don't specify one is -print. All the commands given above are equivalent to themselves with -print tacked on at the end.

find is often used to run commands based on the files found--often, commands that make changes. But there are also other actions whose purpose is to display results, besides -print. Of particular interest is -ls:

find /path/to/folder -name '*bat*' -ls

This gives detailed information on each file, in a multi-column format, similar to (though not quite the same as) what you would see by running ls file.

Best Answer

Related Solutions

Ubuntu – Find file or directory in whole directory structure

Ubuntu – command to find files by searching only part of their names

Finding Files with bat Anywhere

Broadening or Narrowing Your Search, Based on Name

Matching Only Files

Getting Detailed Output

Further Reading

Related Question

Finding Files with `bat` Anywhere