File: calover.sh
   1 #!/bin/sh
   2 
   3 # The MIT License (MIT)
   4 #
   5 # Copyright (c) 2026 pacman64
   6 #
   7 # Permission is hereby granted, free of charge, to any person obtaining a copy
   8 # of this software and associated documentation files (the "Software"), to deal
   9 # in the Software without restriction, including without limitation the rights
  10 # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11 # copies of the Software, and to permit persons to whom the Software is
  12 # furnished to do so, subject to the following conditions:
  13 #
  14 # The above copyright notice and this permission notice shall be included in
  15 # all copies or substantial portions of the Software.
  16 #
  17 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19 # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  20 # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  23 # SOFTWARE.
  24 
  25 
  26 # calover [options...] [files...]
  27 #
  28 # CALendar OVER shows the current date/time, a partial calendar with the 3
  29 # months `around` the current date, shown over more input, if either given as
  30 # or implied.
  31 #
  32 # When given filenames as arguments, their conteints will show below the top
  33 # calendar view. When no filenames are given, but the standard input is being
  34 # piped into, the standard input will be the contents instead.
  35 #
  36 # The options are, available both in single and double-dash versions
  37 #
  38 #   -h, -help    show this help message
  39 
  40 
  41 case "$1" in
  42     -h|--h|-help|--help)
  43         awk '/^# +calover /, /^$/ { gsub(/^# ?/, ""); print }' "$0"
  44         exit 0
  45     ;;
  46 
  47     --) shift ;;
  48 
  49     -*)
  50         printf "unsupported option '%s'\n" "$1" >&2
  51         exit 1
  52     ;;
  53 esac
  54 
  55 # show all non-existing files given
  56 failed=0
  57 for arg in "$@"; do
  58     [ "${arg}" = "-" ] && continue
  59     [ -e "${arg}" ] && continue
  60     printf "no file named \"%s\"\n" "${arg}" >&2
  61     failed=1
  62 done
  63 
  64 [ "${failed}" -gt 0 ] && exit 2
  65 
  66 width="$(tput -T xterm cols)"
  67 
  68 {
  69     # show the current date/time center-aligned
  70     printf \
  71         "%*s\033[38;2;78;154;6m%s\033[0m  \033[38;2;52;101;164m%s\033[0m\n\n" \
  72         "$((width / 2 - 11))" "" "$(date +'%a %b %d %Y')" "$(date +'%H:%M')"
  73 
  74     # debian linux's `cal` can't highlight the current day
  75     if [ -e /usr/bin/ncal ]; then
  76         # `ncal` has a weird way to highlight the current day
  77         ncal -C -3 | sed -E 's/_\x08(.+)_\x08([^ ]+)/\x1b\[7m\1\2\x1b\[0m/'
  78     else
  79         cal -3
  80     fi | awk -v n="$((width / 2 - 32))" '{ printf "%*s%s\n", n, "", $0 }'
  81 
  82     if [ $# -gt 0 ] || [ -p /dev/stdin ]; then
  83         awk 1 "$@"
  84     fi
  85 } | { less -MKiCRS --header=11 2> /dev/null || less -RIMS 2> /dev/null || cat; }