1.\" Copyright (c) 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the Institute of Electrical and Electronics Engineers, Inc. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. Neither the name of the University nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" @(#)touch.1 8.3 (Berkeley) 4/28/95 32.\" 33.Dd June 1, 2018 34.Dt TOUCH 1 35.Os 36.Sh NAME 37.Nm touch 38.Nd change file access and modification times 39.Sh SYNOPSIS 40.Nm 41.Op Fl A Ar [-][[hh]mm]SS 42.Op Fl achm 43.Op Fl r Ar file 44.Op Fl t Ar [[CC]YY]MMDDhhmm[.SS] 45.Op Fl d Ar YYYY-MM-DDThh:mm:SS[.frac][tz] 46.Ar 47.Sh DESCRIPTION 48The 49.Nm 50utility sets the modification and access times of files. 51If any file does not exist, it is created with default permissions. 52.Pp 53By default, 54.Nm 55changes both modification and access times. 56The 57.Fl a 58and 59.Fl m 60flags may be used to select the access time or the modification time 61individually. 62Selecting both is equivalent to the default. 63By default, the timestamps are set to the current time. 64The 65.Fl d 66and 67.Fl t 68flags explicitly specify a different time, and the 69.Fl r 70flag specifies to set the times those of the specified file. 71The 72.Fl A 73flag adjusts the values by a specified amount. 74.Pp 75The following options are available: 76.Bl -tag -width Ds 77.It Fl A 78Adjust the access and modification time stamps for the file by the 79specified value. 80This flag is intended for use in modifying files with incorrectly set 81time stamps. 82.Pp 83The argument is of the form 84.Dq [-][[hh]mm]SS 85where each pair of letters represents the following: 86.Pp 87.Bl -tag -width Ds -compact -offset indent 88.It Ar - 89Make the adjustment negative: the new time stamp is set to be before 90the old one. 91.It Ar hh 92The number of hours, from 00 to 99. 93.It Ar mm 94The number of minutes, from 00 to 59. 95.It Ar SS 96The number of seconds, from 00 to 59. 97.El 98.Pp 99The 100.Fl A 101flag implies the 102.Fl c 103flag: if any file specified does not exist, it will be silently ignored. 104.It Fl a 105Change the access time of the file. 106The modification time of the file is not changed unless the 107.Fl m 108flag is also specified. 109.It Fl c 110Do not create the file if it does not exist. 111The 112.Nm 113utility does not treat this as an error. 114No error messages are displayed and the exit value is not affected. 115.It Fl d 116Change the access and modification times to the specified date time instead 117of the current time of day. 118The argument is of the form 119.Dq YYYY-MM-DDThh:mm:SS[.frac][tz] 120where the letters represent the following: 121.Bl -tag -width Ds -compact -offset indent 122.It Ar YYYY 123At least four decimal digits representing the year. 124.It Ar MM , Ar DD , Ar hh , Ar mm , Ar SS 125As with 126.Fl t 127time. 128.It Ar T 129The letter 130.Li T 131or a space is the time designator. 132.It Ar .frac 133An optional fraction, consisting of a period or a comma followed by one or 134more digits. 135The number of significant digits depends on the kernel configuration and the 136filesystem, and may be zero. 137.It Ar tz 138An optional letter 139.Li Z 140indicating the time is in 141.Tn UTC . 142Otherwise, the time is assumed to be in local time. 143Local time is affected by the value of the 144.Ev TZ 145environment variable. 146.El 147.It Fl h 148If the file is a symbolic link, change the times of the link 149itself rather than the file that the link points to. 150Note that 151.Fl h 152implies 153.Fl c 154and thus will not create any new files. 155.It Fl m 156Change the modification time of the file. 157The access time of the file is not changed unless the 158.Fl a 159flag is also specified. 160.It Fl r 161Use the access and modifications times from the specified file 162instead of the current time of day. 163.It Fl t 164Change the access and modification times to the specified time instead 165of the current time of day. 166The argument is of the form 167.Dq [[CC]YY]MMDDhhmm[.SS] 168where each pair of letters represents the following: 169.Pp 170.Bl -tag -width Ds -compact -offset indent 171.It Ar CC 172The first two digits of the year (the century). 173.It Ar YY 174The second two digits of the year. 175If 176.Dq YY 177is specified, but 178.Dq CC 179is not, a value for 180.Dq YY 181between 69 and 99 results in a 182.Dq CC 183value of 19. 184Otherwise, a 185.Dq CC 186value of 20 is used. 187.It Ar MM 188The month of the year, from 01 to 12. 189.It Ar DD 190the day of the month, from 01 to 31. 191.It Ar hh 192The hour of the day, from 00 to 23. 193.It Ar mm 194The minute of the hour, from 00 to 59. 195.It Ar SS 196The second of the minute, from 00 to 60. 197.El 198.Pp 199If the 200.Dq CC 201and 202.Dq YY 203letter pairs are not specified, the values default to the current 204year. 205If the 206.Dq SS 207letter pair is not specified, the value defaults to 0. 208.El 209.Sh EXIT STATUS 210.Ex -std 211.Sh COMPATIBILITY 212The obsolescent form of 213.Nm , 214where a time format is specified as the first argument, is supported. 215When no 216.Fl r 217or 218.Fl t 219option is specified, there are at least two arguments, and the first 220argument is a string of digits either eight or ten characters in length, 221the first argument is interpreted as a time specification of the form 222.Dq MMDDhhmm[YY] . 223.Pp 224The 225.Dq MM , 226.Dq DD , 227.Dq hh 228and 229.Dq mm 230letter pairs are treated as their counterparts specified to the 231.Fl t 232option. 233If the 234.Dq YY 235letter pair is in the range 39 to 99, the year is set to 1939 to 1999, 236otherwise, the year is set in the 21st century. 237.Sh SEE ALSO 238.Xr utimensat 2 239.Sh STANDARDS 240The 241.Nm 242utility is expected to be a superset of the 243.St -p1003.2 244specification. 245.Sh HISTORY 246A 247.Nm 248utility appeared in 249.At v7 . 250