Home ยป How can I move all non-hidden .jpeg files using shell expansion characters?

How can I move all non-hidden .jpeg files using shell expansion characters?

Solutons:


You can use a shell pattern with [ ] character classes.

To move each file (and folder)

  • that is located directly in the present working directory, and
  • whose name does not start with a . (i.e., the file is not hidden), and
  • whose name ends with .jpg or one of its seven other case variants (like .JPG or .Jpg)

to /tmp, you can use the command:

mv -- *.[Jj][Pp][Gg] /tmp
  • This uses character classes to match any files whose names end in ., then J or j, then P or p, then G or g. Character classes (with [ ]) use more compact syntax than brace expressions ({ }), and also have the benefit that they only expand to names of files that actually exist, so you won’t get error messages even if some case variants of .jpg don’t appear at the end of any filenames. (You’ll still see an error message if no files are matched.)
  • When the shell expands patterns, it excludes files that begin with . by default, so nothing special has to be done to achieve that.
  • The -- option ensures mv interprets everything after it as a filename and not as an option. Thus even if the pattern matches files whose names start with -, they will be treated as literal filenames and not options to mv. (This could alternatively have been achieved by prefixing the pattern with ./, i.e. mv ./*.[Jj][Pp][Gg] /tmp.)

You can enable the nocaseglob shell option and give a simple pattern.

An alternative way is to turn on the nocaseglob shell option, which causes filename patterns to matched case-insensitively. Since you likely don’t need to change this setting for subsequent commands, you can surround the commands that enable nocaseglob and move the files in parentheses so they run in a subshell, so that the calling environment is unaffected:

(shopt -s nocaseglob; mv -- *.jpg /tmp)

Since jpg is only three characters long, you may prefer the above method with character classes. However, for case-sensitive globbing of longer words, it becomes quite handy to be able to set nocaseglob.

What happens if there are files with the same name already in /tmp?

However you decide to specify the pattern of files to be moved, if a file with the same name as one of the files being moved already exists in /tmp, then mv‘s default behavior will be followed, as we have not given mv any options about how to handle a collision. That is to say:

  • If the pre-existing destination file has write permissions for the user running mv, it will be automatically and silently overwritten by the source file.
  • If the pre-existing destination file does not have write permissions for the user running mv, then mv will prompt the user and ask what to do. (Overwriting the file might still succeed in this case, if the user owns the pre-existing destination file.)

To specify different behavior when the destination file already exists, you can use the --backup, -b, -f, -i, -n, or -u options, as documented in:

  • man mv and
  • 11.4 mv: Move (rename) files (in the GNU coreutils reference manual).

Simple:

mv ./*.{j,J}{p,P}{g,G} /path/to/folder/

or alternatively

mv "$(pwd)"/*.{j,J}{p,P}{g,G} /path/to/folder/

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