find: Comparing Timestamps

1 
1 2.3.2 Comparing Timestamps
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1 
1  -- Test: -newerXY reference
1      Succeeds if timestamp 'X' of the file being considered is newer
1      than timestamp 'Y' of the file 'reference'.  The letters 'X' and
1      'Y' can be any of the following letters:
1 
1      'a'
1           Last-access time of 'reference'
1      'B'
1           Birth time of 'reference' (when this is not known, the test
1           cannot succeed)
1      'c'
1           Last-change time of 'reference'
1      'm'
1           Last-modification time of 'reference'
1      't'
1           The 'reference' argument is interpreted as a literal time,
1           rather than the name of a file.  ⇒Date input formats,
1           for a description of how the timestamp is understood.  Tests
1           of the form '-newerXt' are valid but tests of the form
1           '-newertY' are not.
1 
1      For example the test '-newerac /tmp/foo' succeeds for all files
1      which have been accessed more recently than '/tmp/foo' was changed.
1      Here 'X' is 'a' and 'Y' is 'c'.
1 
1      Not all files have a known birth time.  If 'Y' is 'b' and the birth
1      time of 'reference' is not available, 'find' exits with an
1      explanatory error message.  If 'X' is 'b' and we do not know the
1      birth time the file currently being considered, the test simply
1      fails (that is, it behaves like '-false' does).
1 
1      Some operating systems (for example, most implementations of Unix)
1      do not support file birth times.  Some others, for example
1      NetBSD-3.1, do.  Even on operating systems which support file birth
1      times, the information may not be available for specific files.
1      For example, under NetBSD, file birth times are supported on UFS2
1      file systems, but not UFS1 file systems.
1 
1    There are two ways to list files in '/usr' modified after February 1
1 of the current year.  One uses '-newermt':
1 
1      find /usr -newermt "Feb 1"
1 
1    The other way of doing this works on the versions of find before
1 4.3.3:
1 
1      touch -t 02010000 /tmp/stamp$$
1      find /usr -newer /tmp/stamp$$
1      rm -f /tmp/stamp$$
1 
1  -- Test: -anewer file
1  -- Test: -cnewer file
1  -- Test: -newer file
1      True if the file was last accessed (or its status changed, or it
1      was modified) more recently than FILE was modified.  These tests
1      are affected by '-follow' only if '-follow' comes before them on
1      the command line.  ⇒Symbolic Links, for more information on
1      '-follow'.  As an example, to list any files modified since
1      '/bin/sh' was last modified:
1 
1           find . -newer /bin/sh
1 
1  -- Test: -used n
1      True if the file was last accessed N days after its status was last
1      changed.  Useful for finding files that are not being used, and
1      could perhaps be archived or removed to save disk space.
1