The --after-date=date (--newer=date,
-N date) option causes tar to only work on
files whose data modification or status change times are newer than
the date given. If date starts with ‘/’ or ‘.’,
it is taken to be a file name; the data modification time of that file
is used as the date. If you use this option when creating or appending
to an archive, the archive will only include new files. If you use
--after-date when extracting an archive, tar will
only extract files newer than the date you specify.
If you only want tar to make the date comparison based on
modification of the file's data (rather than status
changes), then use the --newer-mtime=date option.
You may use these options with any operation. Note that these options
differ from the --update (-u) operation in that they
allow you to specify a particular date against which tar can
compare when deciding whether or not to archive the files.
Only store files newer than date.
Acts on files only if their data modification or status change times are
later than date. Use in conjunction with any operation.
If date starts with ‘/’ or ‘.’, it is taken to be a file
name; the data modification time of that file is used as the date.
Acts like --after-date, but only looks at data modification times.
These options limit tar to operate only on files which have
been modified after the date specified. A file's status is considered to have
changed if its contents have been modified, or if its owner,
permissions, and so forth, have been changed. (For more information on
how to specify a date, see Date input formats; remember that the
entire date argument must be quoted if it contains any spaces.)
Gurus would say that --after-date tests both the data
modification time (mtime, the time the contents of the file
were last modified) and the status change time (ctime, the time
the file's status was last changed: owner, permissions, etc.)
fields, while --newer-mtime tests only the mtime
To be precise, --after-date checks bothmtime and
ctime and processes the file if either one is more recent than
date, while --newer-mtime only checks mtime and
disregards ctime. Neither does it use atime (the last time the
contents of the file were looked at).
Date specifiers can have embedded spaces. Because of this, you may need
to quote date arguments to keep the shell from parsing them as separate
Please Note:--after-date and --newer-mtime
should not be used for incremental backups. Some files (such as those
in renamed directories) are not selected properly by these options.
See Incremental Dumps.
Published under the terms of the GNU General Public License