How to Ignore Warnings but Keep Error Messages from ‘Find’ Command

bashfindsymlink

I'm trying to run a find command, and due to the way the folder is set up, I keep getting the following warnings several times in my script:

find -L ./server/ -type f -printf '%s %p\n' | <rest of really long complicated script>

OUTPUT

find: File system loop detected; ‘./server/~andreas/root’ is part of the same file system loop as ‘./’.
find: File system loop detected; ‘./server/~bob/root’ is part of the same file system loop as ‘./’.
find: File system loop detected; ‘./server/~charles/root’ is part of the same file system loop as ‘./’.
...

I know why I'm getting these messages. Those symbolic links are intentionally placed there for other scripts to use, so I want to safely ignore those warnings in the console output.

How can I prevent find from displaying warnings like "File system loop detected", but still keep all "real" error messages?

I can't just tell find to ignore every directory named root. And find has a -nowarn option, but I can't get it to work no matter where I place it. And so far I haven't found a "log level" option for find.

Best Answer

If you're using the bash shell, you can use output redirection to suppress specific error messages by filtering stderr through grep:

find ... 2> >(grep -v "File system loop detected") | ...

This is described in the "Process Substitution" section of the bash manual/man pages: https://www.gnu.org/software/bash/manual/html_node/Process-Substitution.html#Process-Substitution

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Find “.git” dirs but ignore some paths; or how does `find -not` work

find has a little bit of sophistication to deal with this case:

If the expression contains no actions other than -prune, -print is performed on all files for which the expression is true.

So explicitly print just the parts you want:

find -type d \( -iname old -prune -o -iname backup -prune -o -iname .git -print \)

avoids searching the old and backup trees at all.

How to set (find) atime in seconds

Note that when you do -mtime <timespec>, the <timespec> checks the age of the file at the time find was started.

Unless you run it in a very small directory tree, find will take several milliseconds (if not seconds or hours) to crawl the directory tree and do a lstat() on every file. So having a precision of shorter than a second doesn't necessarily make a lot of sense.

Also note that not all file systems support time stamps with subsecond granularity.

Having said that, there are a few options.

With the find of many BSDs and the one from schily-tools, you can do:

find . -atime -1s

To find files that have been last accessed less than one second ago (compared to when find was started).

With zsh:

ls -ld -- **/*(Dms-1)

For subsecond granularity, with GNU tools, you can use a reference file whose atime you set with touch:

touch -ad '0.5 seconds ago' ../reference
find . -anewer ../reference

Or with recent versions of perl:

perl -MTime::HiRes=lstat,clock_gettime -MFile::Find -le '
  $start =  clock_gettime(CLOCK_REALTIME) - 0.5;
  find(
    sub {
      my @s = lstat $_;
      print $File::Find::name if @s and $s[8] > $start
    }, ".")'

Best Answer

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Find “.git” dirs but ignore some paths; or how does `find -not` work

How to set (find) atime in seconds

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