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author | Indrajith K L | 2022-12-03 17:00:20 +0530 |
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committer | Indrajith K L | 2022-12-03 17:00:20 +0530 |
commit | f5c4671bfbad96bf346bd7e9a21fc4317b4959df (patch) | |
tree | 2764fc62da58f2ba8da7ed341643fc359873142f /coreutils-5.3.0-bin/man/cat1p/touch.1p.txt | |
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diff --git a/coreutils-5.3.0-bin/man/cat1p/touch.1p.txt b/coreutils-5.3.0-bin/man/cat1p/touch.1p.txt new file mode 100644 index 0000000..151c8a7 --- /dev/null +++ b/coreutils-5.3.0-bin/man/cat1p/touch.1p.txt @@ -0,0 +1,314 @@ +touch(P) touch(P) + + + + + +NAME + touch - change file access and modification times + +SYNOPSIS + touch [-acm][ -r ref_file| -t time] file... + +DESCRIPTION + The touch utility shall change the modification times, + access times, or both of files. The modification time + shall be equivalent to the value of the st_mtime member + of the stat structure for a file, as described in the + System Interfaces volume of IEEE Std 1003.1-2001; the + access time shall be equivalent to the value of + st_atime. + + The time used can be specified by the -t time option- + argument, the corresponding time fields of the file ref- + erenced by the -r ref_file option-argument, or the + date_time operand, as specified in the following sec- + tions. If none of these are specified, touch shall use + the current time (the value returned by the equivalent + of the time() function defined in the System Interfaces + volume of IEEE Std 1003.1-2001). + + For each file operand, touch shall perform actions + equivalent to the following functions defined in the + System Interfaces volume of IEEE Std 1003.1-2001: + + If file does not exist, a creat() function call is made + with the file operand used as the path argument and the + value of the bitwise-inclusive OR of S_IRUSR, S_IWUSR, + S_IRGRP, S_IWGRP, S_IROTH, and S_IWOTH used as the mode + argument. + + The utime() function is called with the following argu- + ments: <ol type="a"> + + The file operand is used as the path argument. + + The utimbuf structure members actime and modtime are + determined as described in the OPTIONS section. + +OPTIONS + The touch utility shall conform to the Base Definitions + volume of IEEE Std 1003.1-2001, Section 12.2, Utility + Syntax Guidelines. + + The following options shall be supported: + + -a Change the access time of file. Do not change the + modification time unless -m is also specified. + + -c Do not create a specified file if it does not + exist. Do not write any diagnostic messages con- + cerning this condition. + + -m Change the modification time of file. Do not + change the access time unless -a is also speci- + fied. + + -r ref_file + Use the corresponding time of the file named by + the pathname ref_file instead of the current + time. + + -t time + Use the specified time instead of the current + time. The option-argument shall be a decimal num- + ber of the form: + + + [[CC]YY]MMDDhhmm[.SS] + + where each two digits represents 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 (the century). + + YY The second two digits of the year. + + SS The second of the minute [00,60]. + + + Both CC and YY shall be optional. If neither is given, + the current year shall be assumed. If YY is specified, + but CC is not, CC shall be derived as follows: + If YY is: CC becomes: + [69,99] 19 + [00,68] 20 + + Note: It is expected that in a future version of + IEEE Std 1003.1-2001 the default century inferred + from a 2-digit year will change. (This would + apply to all commands accepting a 2-digit year as + input.) + + + The resulting time shall be affected by the value of the + TZ environment variable. If the resulting time value + precedes the Epoch, touch shall exit immediately with an + error status. The range of valid times past the Epoch + is implementation-defined, but it shall extend to at + least the time 0 hours, 0 minutes, 0 seconds, January 1, + 2038, Coordinated Universal Time. Some implementations + may not be able to represent dates beyond January 18, + 2038, because they use signed int as a time holder. + + The range for SS is [00,60] rather than [00,59] because + of leap seconds. If SS is 60, and the resulting time, as + affected by the TZ environment variable, does not refer + to a leap second, the resulting time shall be one second + after a time where SS is 59. If SS is not given a value, + it is assumed to be zero. + + + If neither the -a nor -m options were specified, touch + shall behave as if both the -a and -m options were spec- + ified. + +OPERANDS + The following operands shall be supported: + + file A pathname of a file whose times shall be modi- + fied. + + +STDIN + Not used. + +INPUT FILES + None. + +ENVIRONMENT VARIABLES + The following environment variables shall affect the + execution of touch: + + LANG Provide a default value for the internationaliza- + tion variables that are unset or null. (See the + Base Definitions volume of IEEE Std 1003.1-2001, + Section 8.2, Internationalization Variables for + the precedence of internationalization variables + used to determine the values of locale cate- + gories.) + + LC_ALL If set to a non-empty string value, override the + values of all the other internationalization + variables. + + LC_CTYPE + Determine the locale for the interpretation of + sequences of bytes of text data as characters + (for example, single-byte as opposed to multi- + byte characters in arguments). + + LC_MESSAGES + Determine the locale that should be used to + affect the format and contents of diagnostic mes- + sages written to standard error. + + NLSPATH + Determine the location of message catalogs for + the processing of LC_MESSAGES . + + TZ Determine the timezone to be used for interpret- + ing the time option-argument. If TZ is unset or + null, an unspecified default timezone shall be + used. + + +ASYNCHRONOUS EVENTS + Default. + +STDOUT + Not used. + +STDERR + The standard error shall be used only for diagnostic + messages. + +OUTPUT FILES + None. + +EXTENDED DESCRIPTION + None. + +EXIT STATUS + The following exit values shall be returned: + + 0 The utility executed successfully and all + requested changes were made. + + >0 An error occurred. + + +CONSEQUENCES OF ERRORS + Default. + + The following sections are informative. + +APPLICATION USAGE + The interpretation of time is taken to be seconds since + the Epoch (see the Base Definitions volume of + IEEE Std 1003.1-2001, Section 4.14, Seconds Since the + Epoch). It should be noted that implementations conform- + ing to the System Interfaces volume of + IEEE Std 1003.1-2001 do not take leap seconds into + account when computing seconds since the Epoch. When + SS=60 is used, the resulting time always refers to 1 + plus seconds since the Epoch for a time when SS=59. + + Although the -t time option-argument specifies values in + 1969, the access time and modification time fields are + defined in terms of seconds since the Epoch (00:00:00 on + 1 January 1970 UTC). Therefore, depending on the value + of TZ when touch is run, there is never more than a few + valid hours in 1969 and there need not be any valid + times in 1969. + + One ambiguous situation occurs if -t time is not speci- + fied, -r ref_file is not specified, and the first oper- + and is an eight or ten-digit decimal number. A portable + script can avoid this problem by using: + + + touch -- file + + or: + + + touch ./file + + in this case. + +EXAMPLES + None. + +RATIONALE + The functionality of touch is described almost entirely + through references to functions in the System Interfaces + volume of IEEE Std 1003.1-2001. In this way, there is no + duplication of effort required for describing such side + effects as the relationship of user IDs to the user + database, permissions, and so on. + + There are some significant differences between the touch + utility in this volume of IEEE Std 1003.1-2001 and those + in System V and BSD systems. They are upwards-compatible + for historical applications from both implementations: + + In System V, an ambiguity exists when a pathname that is + a decimal number leads the operands; it is treated as a + time value. In BSD, no time value is allowed; files may + only be touched to the current time. The -t time con- + struct solves these problems for future conforming + applications (note that the -t option is not historical + practice). + + The inclusion of the century digits, CC, is also new. + Note that a ten-digit time value is treated as if YY, + and not CC, were specified. The caveat about the range + of dates following the Epoch was included as recognition + that some implementations are not able to represent + dates beyond 18 January 2038 because they use signed int + as a time holder. + + The -r option was added because several comments + requested this capability. This option was named -f in + an early proposal, but was changed because the -f option + is used in the BSD version of touch with a different + meaning. + + At least one historical implementation of touch incre- + mented the exit code if -c was specified and the file + did not exist. This volume of IEEE Std 1003.1-2001 + requires exit status zero if no errors occur. + +FUTURE DIRECTIONS + Applications should use the -r or -t options. + +SEE ALSO + date , the System Interfaces volume of + IEEE Std 1003.1-2001, creat(), time(), utime(), the Base + Definitions volume of IEEE Std 1003.1-2001, <sys/stat.h> + +COPYRIGHT + Portions of this text are reprinted and reproduced in + electronic form from IEEE Std 1003.1, 2003 Edition, + Standard for Information Technology -- Portable Operat- + ing System Interface (POSIX), The Open Group Base Speci- + fications Issue 6, Copyright (C) 2001-2003 by the Insti- + tute of Electrical and Electronics Engineers, Inc and + The Open Group. In the event of any discrepancy between + this version and the original IEEE and The Open Group + Standard, the original IEEE and The Open Group Standard + is the referee document. The original Standard can be + obtained online at http://www.open- + group.org/unix/online.html . + + + +POSIX 2003 touch(P) |