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TOUCH(1)                                                              TOUCH(1)



NAME
       touch - change file timestamps

SYNOPSIS
       touch[-acm][-r ref_file|-t time][--] file...

       Obsolescent version:
       touch[-acm][ugly_time] file...

       GNU version:
       touch[-acfm][-r    file][-t    decimtime][-d    time]
       [--time={atime,access,use,mtime,modify}][--date=time][--refer-
       ence=file][--no-create][--help][--version][--] file...

DESCRIPTION
       touch  changes the access and/or modification timestamps of each speci-
       fied file.  These timestamps are changed to the  current  time,  unless
       the  -r option is specified, in which case they are changed to the cor-
       responding timestamps of the file ref_file, or the -t option is  speci-
       fied, in which case they are changed to the specified time.  Both times
       are changed when neither or both of the -a and -m  options  are  given.
       Only  the  access  or only the modification time is changed when one of
       the options -a and -m is given.  If the file did not exist yet,  it  is
       created  (as  an  empty  file  with  mode 0666, modified by the umask),
       unless the -c option is given.

POSIXOPTIONS
       -a     Change the access time of file.

       -c     Do not create file.

       -m     Change the modification time of file.

       -r ref_file
              Use the corresponding timestamp of ref_file as the new value for
              the changed timestamp(s).

       -t time
              Use  the  specified time as the new value for the changed times-
              tamp(s).  The argument is a decimal number of the form
                  [[CC]YY]MMDDhhmm[.SS]
              with the obvious meaning. If CC is not specified, the year  CCYY
              is  taken to be in the range 1969-2068.  If SS is not specified,
              it is taken to be 0. It may be specified in the  range  0-61  so
              that  it  is  possible  to refer to leap seconds.  The resulting
              time is taken as a time for the time zone specified by the envi-
              ronment  variable  TZ. It is an error if the resulting time pre-
              cedes 1 January 1970.

       --     Terminate option list.

POSIXDETAILS
       The second form of invocation has the disadvantage that there  is  some
       ambiguity  as  to whether ugly_time is a time or a file argument. It is
       taken to be a time when no -r or -t option is  present,  there  are  at
       least  two  arguments, and the first argument is an eight- or ten-digit
       decimal integer.  The format of ugly_time is MMDDhhmm[yy], where an  yy
       in  the  range  69-99  denotes  a  year  in the range 1969-1999, and an
       unspecified yy denotes the current year.  This form is obsolete.

GNUDETAILS
       If the first file would be a valid argument to the  -t  option  and  no
       timestamp  is  given  with any of the -d, -r or -t options and the '--'
       argument is not given, that argument is interpreted as the time for the
       other files instead of as a file name.

       If changing both the access and modification times to the current time,
       touch can change the timestamps for files that the user running it does
       not own but has write permission for.  Otherwise, the user must own the
       files.

GNUOPTIONS
       -a,--time=atime,--time=access,--time=use
              Change the access time only.

       -c,--no-create
              Do not create files that do not exist.

       -d,--date=time
              Use time instead of the current  time.   It  can  contain  month
              names, time zones, 'am' and 'pm', etc.

       -f     Ignored; for compatibility with BSD versions of touch(1).

       -m,--time=mtime,--time=modify
              Change the modification time only.

       -r file,--reference=file
              Use the times of the reference file instead of the current time.

       -t decimtime
              Here decimtime has  the  format  MMDDhhmm[[CC]YY][.ss]  Use  the
              argument  (months,  days,  hours,  minutes, optional century and
              years, optional seconds) instead of the current time.  Note that
              this format violates the POSIX specification.

GNUSTANDARDOPTIONS
       --help Print  a usage message on standard output and exit successfully.

       --version
              Print version information on standard output, then exit success-
              fully.

       --     Terminate option list.

ENVIRONMENT
       The variable TZ is used to interpret explicitly given times.  The vari-
       ables LANG, LC_ALL, LC_CTYPE and LC_MESSAGES have the usual meaning.

CONFORMINGTO
       POSIX 1003.2 describes a syntax for the argument of the -t option  that
       differs from that used by the GNU implementation.

EXAMPLEOFUSE
       The  command  'touch  foo' will create the file foo if it didn't exist,
       and change the time of last modification to now.  It is often  used  to
       guide the actions of make.

NOTES
       This  page describes touch as found in the fileutils-4.0 package; other
       versions may  differ  slightly.   Mail  corrections  and  additions  to
       aebcwi.nl.     Report    bugs    in    the   program   to   fileutils-
       bugsgnu.edu.



GNU fileutils 4.0                   1998-11                           TOUCH(1)