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touch(1)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | OPERANDS | USAGE | ENVIRONMENT VARIABLES | EXIT STATUS | ATTRIBUTES | SEE ALSO | NOTES

NAME

touch, settime- change file access and modification times

SYNOPSIS

touch [-acm] [-r ref_file| -t time] file...
touch [-acm] [date_time] file...
settime [-f ref_file] [date_time] file...

DESCRIPTION

The touch utility sets the access and modification times of each file. The file operand is created if it does not already exist.

The time used can be specified by -t time, by the corresponding time fields of the file referenced by -r ref_file, or by the date_time operand. If none of these are specified, touch uses the current time (the value returned by the time(2) function).

If neither the -a nor -m options are specified, touch updates both the modification and access times.

A user with write access to a file, but who is not the owner of the file or a super-user, can change the modification and access times of that file only to the current time. Attempts to set a specific time with touch will result in an error.

The settime utility is equivalent to touch -c [date_time] file.

OPTIONS

touch

The following options are supported for the touch utility:

-a

Changes the access time of file. Does not change the modification time unless -m is also specified.

-c

Does not create a specified file if it does not exist. Does not write any diagnostic messages concerning this condition.

-m

Changes the modification time of file. Does not change the access time unless -a is also specified.

-r ref_file

Uses the corresponding times of the file named by ref_file instead of the current time.

-t time

Uses the specified time instead of the current time. time will be a decimal number of the form:

---

[[CC]YY]MMDDhhmm [.SS]

---

where each two digits represent the following:

MM

The month of the year [01-12].

DD

The day of the month [01-31].

hh

The hour of the day [00-23].

mm

The minute of the hour [00-59].

CC

The first two digits of the year.

YY

The second two digits of the year.

SS

The second of the minute [00-61].

Both CC and YY are optional. If neither is given, the current year will be assumed. If YY is specified, but CC is not, CC will be derived as follows:

If YY is:	CC becomes:
69-99	19
00-38	20
39-68	ERROR

The resulting time will be affected by the value of the TZ environment variable. If the resulting time value precedes the Epoch, touch will exit immediately with an error status. The range of valid times is the Epoch to January 18, 2038.

The range for SS is [00-61] rather than [00-59] because of leap seconds. If SS is 60 or 61, and the resulting time, as affected by the TZ environment variable, does not refer to a leap second, the resulting time will be one or two seconds after a time where SS is 59. If SS is not given, it is assumed to be 0.

settime

The following option is supported for the settime utility:

-f ref_file

Uses the corresponding times of the file named by ref_file instead of the current time.

OPERANDS

The following operands are supported for the touch and settime utilities:

file

A path name of a file whose times are to be modified.

date_time

Uses the specified date_time instead of the current time. This operand is a decimal number of the form:

---

MMDDhhmm[YY]

---

where each two digits represent the following:

MM

The month of the year [01-12].

DD

The day of the month [01-31].

hh

The hour of the day [00-23].

mm

The minute of the hour [00-59].

YY

The second two digits of the year.

YY is optional. If it is omitted, the current year will be assumed. If YY is specified, the year will be derived as follows:

YY	Corresponding Year
69-99	1969-1999
00-38	2000-2038
39-68	ERROR

If no -r option is specified, no -t option is specified, at least two operands are specified, and the first operand is an eight- or ten-digit decimal integer, the first operand will be assumed to be a date_time operand; otherwise, the first operand will be assumed to be a file operand.

USAGE

See largefile(5) for the description of the behavior of touch when encountering files greater than or equal to 2 Gbyte ( 2³¹ bytes).

ENVIRONMENT VARIABLES

See environ(5) for descriptions of the following environment variables that affect the execution of touch: LANG, LC_ALL, LC_CTYPE, LC_MESSAGES, and NLSPATH.

TZ

Determine the timezone to be used for interpreting the time option-argument or the date_time operand.

EXIT STATUS

The following exit values are returned:

0

The touch utility executed successfully and all requested changes were made.

>0

An error occurred. The touch utility returned the number of files for which the times could not be successfully modified.

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE	ATTRIBUTE VALUE
Availability	SUNWcsu
CSI	enabled

SEE ALSO

time(2), attributes(5), environ(5), largefile(5)

NOTES

Users familiar with the BSD environment will find that for the touch utility, the -f option is accepted but ignored. The -f option is unnecessary because touch will succeed for all files owned by the user regardless of the permissions on the files.

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | OPERANDS | USAGE | ENVIRONMENT VARIABLES | EXIT STATUS | ATTRIBUTES | SEE ALSO | NOTES