freebsd-dev/usr.bin/touch/touch.1

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.\"     @(#)touch.1	8.3 (Berkeley) 4/28/95
.\" $FreeBSD$
.\"
.Dd April 28, 1995
.Dt TOUCH 1
.Os
.Sh NAME
.Nm touch
.Nd change file access and modification times
.Sh SYNOPSIS
.Nm
.Op Fl A Ar [-][[hh]mm]SS
.Op Fl acfhm
.Op Fl r Ar file
.Op Fl t Ar [[CC]YY]MMDDhhmm[.SS]
.Ar
.Sh DESCRIPTION
The
.Nm
utility sets the modification and access times of files.
If any file does not exist, it is created with default permissions.
.Pp
By default,
.Nm 
changes both modification and access times.  The
.Fl a
and 
.Fl m
flags may be used to select the access time or the modification time
individually.
Selecting both is equivalent to the default.
The base times for the modification are both set to the current time.
The 
.Fl t
flag explicitly specifies a single time for both values, and the
.Fl r
flag specifies to set the times from those of a different file.
The 
.Fl A
flag adjusts the values by a specified amount.
This adjustment is done after first establishing the base times.
.Pp
The following options are available:
.Bl -tag -width Ds
.It Fl A 
Adjust the access and modification time stamps for the file by the
specified value.
This flag is intended for use in modifying files with a time stamp
relative to an incorrect time zone.
It always modifies both the access time and the modification time.
.Pp
The argument is of the form
.Dq [-][[hh]mm]SS
where each pair of letters represents the following:
.Pp
.Bl -tag -width Ds -compact -offset indent
.It Ar -
Make the adjustment negative: the new time stamp is set to be before
the old one.
.It Ar hh
The hour of the day, from 00 to 23.
.It Ar mm
The minute of the hour, from 00 to 59.
.It Ar SS
The second of the minute, from 00 to 59.
.El
.Pp
When used in conjunction with the
.Fl a
flag only, the modification time is adjusted by the time specified as
argument to the
.Fl A
flag, while the access time is modified from the base time described
above.
Similarly, when used in conjunction with the
.Fl m
flag only, the access time is adjusted by the time specified as
argument to the
.Fl A
flag, while the access time is modified from the base time described
above.
.Pp
If the file does not exist, and creation is allowed,
.Fl A
does not change its time stamps.
.It Fl a
Change the access time of the file.
The modification time of the file is not changed unless one of the
.Fl A
or
.Fl m
flags is also specified.
.It Fl c
Do not create the file if it does not exist.
The
.Nm
utility does not treat this as an error.
No error messages are displayed and the exit value is not affected.
.It Fl f
Attempt to force the update, even if the file permissions do not
currently permit it.
.It Fl h
If the file is a symbolic link, change the times of the link
itself rather than the file that the link points to.
Note that
.Fl h
implies
.Fl c
and thus will not create any new files.
.It Fl m
Change the modification time of the file.
The access time of the file is not changed unless one of the
.Fl A
or
.Fl a
flags is also specified.
.It Fl r
Use the access and modifications times from the specified file
instead of the current time of day.
.It Fl t
Change the access and modification times to the specified time.
The argument is of the form
.Dq [[CC]YY]MMDDhhmm[.SS]
where each pair of letters represents the following:
.Pp
.Bl -tag -width Ds -compact -offset indent
.It Ar CC
The first two digits of the year (the century).
.It Ar YY
The second two digits of the year.
If
.Dq YY
is specified, but
.Dq CC
is not, a value for
.Dq YY
between 69 and 99 results in a
.Dq CC
value of 19.
Otherwise, a
.Dq CC
value of 20 is used.
.It Ar MM
The month of the year, from 01 to 12.
.It Ar DD
the day of the month, from 01 to 31.
.It Ar hh
The hour of the day, from 00 to 23.
.It Ar mm
The minute of the hour, from 00 to 59.
.It Ar SS
The second of the minute, from 00 to 61.
.El
.Pp
If the
.Dq CC
and
.Dq YY
letter pairs are not specified, the values default to the current
year.
If the
.Dq SS
letter pair is not specified, the value defaults to 0.
.El
.Sh EXIT STATUS
.Ex -std
.Sh COMPATIBILITY
The obsolescent form of
.Nm ,
where a time format is specified as the first argument, is supported.
When no
.Fl r
or
.Fl t
option is specified, there are at least two arguments, and the first
argument is a string of digits either eight or ten characters in length,
the first argument is interpreted as a time specification of the form
.Dq MMDDhhmm[YY] .
.Pp
The
.Dq MM ,
.Dq DD ,
.Dq hh
and
.Dq mm
letter pairs are treated as their counterparts specified to the
.Fl t
option.
If the
.Dq YY
letter pair is in the range 39 to 99, the year is set to 1939 to 1999,
otherwise, the year is set in the 21st century.
.Sh SEE ALSO
.Xr utimes 2
.Sh STANDARDS
The
.Nm
utility is expected to be a superset of the
.St -p1003.2
specification.
.Sh HISTORY
A
.Nm
utility appeared in
.At v7 .