Command line: piping find results to rm

I'm trying to work out a command which deletes sql files older than 15 days.

The find part is working but not the rm.

rm -f | find -L /usr/www2/bar/htdocs/foo/rsync/httpdocs/db_backups -type f  \( -name '*.sql' \) -mtime +15

It kicks out a list of exactly the files I want deleted but is not deleting them. The paths are correct.

usage: rm [-f | -i] [-dIPRrvW] file ...
       unlink file
/usr/www2/bar/htdocs/foo/rsync/httpdocs/db_backups/20120601.backup.sql
...
/usr/www2/bar/htdocs/foo/rsync/httpdocs/db_backups/20120610.backup.sql

What am I doing wrong?

You are actually piping rm's output to the input of find. What you want is to use the output of find as arguments to rm:

find -type f -name '*.sql' -mtime +15 | xargs rm

xargs is the command that "converts" its standard input into arguments of another program, or, as they more accurately put it on the man page,

> build and execute command lines from standard input

Note that if file names can contain whitespace characters, you should correct for that:

find -type f -name '*.sql' -mtime +15 -print0 | xargs -0 rm

But actually, find has a shortcut for this: the -delete option:

find -type f -name '*.sql' -mtime +15 -delete

Please be aware of the following warnings in man find:

  Warnings:  Don't  forget that the find command line is evaluated
  as an expression, so putting -delete first will make find try to
  delete everything below the starting points you specified.  When
  testing a find command line that you later intend  to  use  with
  -delete,  you should explicitly specify -depth in order to avoid
  later surprises.  Because -delete  implies  -depth,  you  cannot
  usefully use -prune and -delete together.

_{P.S. Note that piping directly to rm isn't an option, because rm doesn't expect filenames on standard input. What you are currently doing is piping them backwards.}

find /usr/www/bar/htdocs -mtime +15 -exec rm {} \;

Will select files in /usr/www/bar/htdocs older than 15 days and remove them.

Another simpler method is to use locate command. Then, pipe the result to xargs.

For example,

locate file | xargs rm

Assuming you aren't in the directory containing the *.sql backup files:

find /usr/www2/bar/htdocs/foo/rsync/httpdocs/db_backups/*.sql -mtime +15 -exec rm -v {} \;

The -v option above is handy it will verbosely output which files are being deleted as they are removed.

I like to list the files that will be deleted first to be sure. E.g:

find /usr/www2/bar/htdocs/foo/rsync/httpdocs/db_backups/*.sql -mtime +15 -exec ls -lrth {} \;

Use xargs to pass arguments, with the option -rd '\n' to ignore spaces in names:

> "${command}" | xargs -rd '\n' rm

Include --force if you want to also remove read only files.