lib/mdate-sh

   1 #!/bin/sh
   2 # Get modification time of a file or directory and pretty-print it.
   3
   4 scriptversion=2023-11-23.18; # UTC
   5
   6 # Copyright (C) 1995-2024 Free Software Foundation, Inc.
   7 # written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, June 1995
   8 #
   9 # This program is free software; you can redistribute it and/or modify
  10 # it under the terms of the GNU General Public License as published by
  11 # the Free Software Foundation; either version 2, or (at your option)
  12 # any later version.
  13 #
  14 # This program is distributed in the hope that it will be useful,
  15 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 # GNU General Public License for more details.
  18 #
  19 # You should have received a copy of the GNU General Public License
  20 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
  21
  22 # As a special exception to the GNU General Public License, if you
  23 # distribute this file as part of a program that contains a
  24 # configuration script generated by Autoconf, you may include it under
  25 # the same distribution terms that you use for the rest of that program.
  26
  27 # This file is maintained in Automake, please report
  28 # bugs to <bug-automake@gnu.org> or send patches to
  29 # <automake-patches@gnu.org>.
  30
  31 if test -n "${ZSH_VERSION+set}" && (emulate sh) >/dev/null 2>&1; then
  32   emulate sh
  33   NULLCMD=:
  34   # Pre-4.2 versions of Zsh do word splitting on ${1+"$@"}, which
  35   # is contrary to our usage.  Disable this feature.
  36   alias -g '${1+"$@"}'='"$@"'
  37   setopt NO_GLOB_SUBST
  38 fi
  39
  40 case $1 in
  41   '')
  42      echo "$0: No file.  Try '$0 --help' for more information." 1>&2
  43      exit 1;
  44      ;;
  45   -h | --h*)
  46     cat <<\EOF
  47 Usage: mdate-sh [--help] [--version] FILE
  48
  49 Pretty-print the modification day of FILE, in the format:
  50 1 January 1970
  51
  52 Report bugs to <bug-automake@gnu.org>.
  53 GNU Automake home page: <https://www.gnu.org/software/automake/>.
  54 General help using GNU software: <https://www.gnu.org/gethelp/>.
  55 EOF
  56     exit $?
  57     ;;
  58   -v | --v*)
  59     echo "mdate-sh $scriptversion"
  60     exit $?
  61     ;;
  62 esac
  63
  64 error ()
  65 {
  66   echo "$0: $1" >&2
  67   exit 1
  68 }
  69
  70
  71 # Prevent date giving response in another language.
  72 LANG=C
  73 export LANG
  74 LC_ALL=C
  75 export LC_ALL
  76 LC_TIME=C
  77 export LC_TIME
  78
  79 # Use UTC to get reproducible result.
  80 TZ=UTC0
  81 export TZ
  82
  83 # GNU ls changes its time format in response to the TIME_STYLE
  84 # variable.  Since we cannot assume 'unset' works, revert this
  85 # variable to its documented default.
  86 if test "${TIME_STYLE+set}" = set; then
  87   TIME_STYLE=posix-long-iso
  88   export TIME_STYLE
  89 fi
  90
  91 save_arg1=$1
  92
  93 # Find out how to get the extended ls output of a file or directory.
  94 if ls -L /dev/null 1>/dev/null 2>&1; then
  95   ls_command='ls -L -l -d'
  96 else
  97   ls_command='ls -l -d'
  98 fi
  99 # Avoid user/group names that might have spaces, when possible.
 100 if ls -n /dev/null 1>/dev/null 2>&1; then
 101   ls_command="$ls_command -n"
 102 fi
 103
 104 # A 'ls -l' line looks as follows on OS/2.
 105 #  drwxrwx---        0 Aug 11  2001 foo
 106 # This differs from Unix, which adds ownership information.
 107 #  drwxrwx---   2 root  root      4096 Aug 11  2001 foo
 108 #
 109 # To find the date, we split the line on spaces and iterate on words
 110 # until we find a month.  This cannot work with files whose owner is a
 111 # user named "Jan", or "Feb", etc.  However, it's unlikely that '/'
 112 # will be owned by a user whose name is a month.  So we first look at
 113 # the extended ls output of the root directory to decide how many
 114 # words should be skipped to get the date.
 115
 116 # On HPUX /bin/sh, "set" interprets "-rw-r--r--" as options, so the "x" below.
 117 set x`$ls_command /`
 118
 119 # Find which argument is the month.
 120 month=
 121 command=
 122 until test $month
 123 do
 124   test $# -gt 0 || error "failed parsing '$ls_command /' output"
 125   shift
 126   # Add another shift to the command.
 127   command="$command shift;"
 128   case $1 in
 129     Jan) month=January; nummonth=1;;
 130     Feb) month=February; nummonth=2;;
 131     Mar) month=March; nummonth=3;;
 132     Apr) month=April; nummonth=4;;
 133     May) month=May; nummonth=5;;
 134     Jun) month=June; nummonth=6;;
 135     Jul) month=July; nummonth=7;;
 136     Aug) month=August; nummonth=8;;
 137     Sep) month=September; nummonth=9;;
 138     Oct) month=October; nummonth=10;;
 139     Nov) month=November; nummonth=11;;
 140     Dec) month=December; nummonth=12;;
 141   esac
 142 done
 143
 144 test -n "$month" || error "failed parsing '$ls_command /' output"
 145
 146 # Get the extended ls output of the file or directory.
 147 set dummy x`eval "$ls_command \"\\\$save_arg1\""`
 148
 149 # Remove all preceding arguments
 150 eval $command
 151
 152 # Because of the dummy argument above, month is in $2.
 153 #
 154 # On a POSIX system, we should have
 155 #
 156 # $# = 5
 157 # $1 = file size
 158 # $2 = month
 159 # $3 = day
 160 # $4 = year or time
 161 # $5 = filename
 162 #
 163 # On Darwin 7.7.0 and 7.6.0, we have
 164 #
 165 # $# = 4
 166 # $1 = day
 167 # $2 = month
 168 # $3 = year or time
 169 # $4 = filename
 170
 171 # Get the month.
 172 case $2 in
 173   Jan) month=January; nummonth=1;;
 174   Feb) month=February; nummonth=2;;
 175   Mar) month=March; nummonth=3;;
 176   Apr) month=April; nummonth=4;;
 177   May) month=May; nummonth=5;;
 178   Jun) month=June; nummonth=6;;
 179   Jul) month=July; nummonth=7;;
 180   Aug) month=August; nummonth=8;;
 181   Sep) month=September; nummonth=9;;
 182   Oct) month=October; nummonth=10;;
 183   Nov) month=November; nummonth=11;;
 184   Dec) month=December; nummonth=12;;
 185 esac
 186
 187 case $3 in
 188   ???*) day=$1;;
 189   *) day=$3; shift;;
 190 esac
 191
 192 # Here we have to deal with the problem that the ls output gives either
 193 # the time of day or the year.
 194 case $3 in
 195   *:*) set `date`; eval year=\$$#
 196        case $2 in
 197          Jan) nummonthtod=1;;
 198          Feb) nummonthtod=2;;
 199          Mar) nummonthtod=3;;
 200          Apr) nummonthtod=4;;
 201          May) nummonthtod=5;;
 202          Jun) nummonthtod=6;;
 203          Jul) nummonthtod=7;;
 204          Aug) nummonthtod=8;;
 205          Sep) nummonthtod=9;;
 206          Oct) nummonthtod=10;;
 207          Nov) nummonthtod=11;;
 208          Dec) nummonthtod=12;;
 209        esac
 210        # For the first six month of the year the time notation can also
 211        # be used for files modified in the last year.
 212        if (expr $nummonth \> $nummonthtod) > /dev/null;
 213        then
 214          year=`expr $year - 1`
 215        fi;;
 216   *) year=$3;;
 217 esac
 218
 219 # The result.
 220 echo $day $month $year
 221
 222 # Local Variables:
 223 # mode: shell-script
 224 # sh-indentation: 2
 225 # eval: (add-hook 'before-save-hook 'time-stamp)
 226 # time-stamp-start: "scriptversion="
 227 # time-stamp-format: "%:y-%02m-%02d.%02H"
 228 # time-stamp-time-zone: "UTC0"
 229 # time-stamp-end: "; # UTC"
 230 # End: