file permissions problem?

[Angel25]

I was trying to fix file permissions for files copied from ntfs drives and I ran this command

find /home/user -type f -exec chmod -c 644 {} ";"

That changed the permissions for many files in hidden .folders in my home folder from 664 to 644, and some from 600 to 664. Is that a problem? How can I fix?

[dave0808]

You may or may not know, but 664 to 644 has simply turned off write-permission for group access. Most, if not all, files that you changed will be in your group anyway, so not a problem.

and some from 600 to 664.

I'm assuming this is a typo and you mean "600 to 644". Here, you have given read permission to group and to "others", aka 'any account' on the system. Whether this is a problem or not, only you can decide.

Potentially more annoying is if you had any files that were marked as "executable" as these files will no longer be so - as in you won't be able to run them until you make them executable again. These may include files like local shell scripts or any AppImages.

The "bad" news is that there's no undo for this kind of operation. But it is not all bad news.

If you are the only user on this system, and if you're concerned about system processes accessing your files, then you could run the command again and use 640 (or o-r) instead, which will remove read access for "other". Next, if you had any executable files, they will simply fail the next time you try to run them, at that point you can add the executable bit once more, use u+x instead of absolute octal numbers.

Alternatively, if you have a VERY recent and COMPLETE backup of your home directory, you could use it as a template to see what the permissions were and change them back on your live home directory. This would be quite tedious though.

[Termy]

If any of the files needed the execute bit set, then you will have to sort that out yourself, but since they're from NTFS, I'm guessing that's not a problem here.

The command you ran will only change the permissions (mode) of all (including those hidden) files in '/home/user' to 644 (rw-r--r--), not 664 (rw-rw-r--). For most people, 700 (rwx------) for directories and executable files, and 600 (rw-------) for all other files is sufficient.

Alternatively, if you have a VERY recent and COMPLETE backup of your home directory, you could use it as a template to see what the permissions were and change them back on your live home directory. This would be quite tedious though.

This can be fairly easily automated with a script, so if the OP does have such a backup, I imagine someone would be up for that task. It'd be a case of a few loops and using chmod(1) with stat(1) to determine and correct the modes.

[Angel25]

Thanks for your help

Ultimately, I spent a lot of time changing them back manually

[Termy]

Thanks for your help

Ultimately, I spent a lot of time changing them back manually

I'm sorry for your loss (of time). At least it's sorted, now.

[Aztaroth]

To change the permissions of all files of a special permission type :

Code: Select all

find <mypath> -type f -perm 644 -exec chmod 664 {} \;

will set the permissions of all files that have a 644 perm to 664 in <mypath>.
Of course, you should know the meaning of the permission octals you put in.
If it's easier, you can also use symbolic permission labels : find . -perm -220 can be 'translated' into find . -perm -g+w,u+w. This example comes from the man find manual.

PS : Next time, use -not -name '.*' in your original command if you don't want to hit hidden files beginning with a dot.