funcs/gsu

   1 #!/bin/bash
   2 # gsu -- the global subcommand utility
   3 # (C) 2006-2007 Andre Noll
   4
   5 gsu_init_errors()
   6 {
   7         gsu_errors="
   8 GSU_SUCCESS                     success
   9 E_GSU_BAD_COMMAND               invalid command
  10 E_GSU_NOT_A_NUMBER              not a number
  11 $gsu_errors
  12 "
  13         local a b i
  14         local i=0
  15         while read a b; do
  16                 if test -z "$a"; then
  17                         continue
  18                 fi
  19                 #echo "a:$a,  b: $b"
  20                 gsu_error_txt[i]="$b"
  21                 eval $a=$i
  22                 i=$((i + 1))
  23         done << EOF
  24         $gsu_errors
  25 EOF
  26 }
  27 export -f gsu_init_errors
  28
  29 # check if $1 is a number
  30 gsu_is_a_number()
  31 {
  32         result="$1"
  33         if test "$1" -eq "$1" &> /dev/null; then
  34                 ret=$GSU_SUCCESS
  35         else
  36                 ret=-$E_GSU_NOT_A_NUMBER
  37         fi
  38 }
  39 export -f gsu_is_a_number
  40
  41 gsu_short_msg()
  42 {
  43         echo "$1" 1>&2
  44 }
  45 export -f gsu_short_msg
  46
  47 gsu_msg()
  48 {
  49         gsu_short_msg "$gsu_self: $1"
  50 }
  51 export -f gsu_msg
  52
  53 gsu_date_msg()
  54 {
  55         gsu_short_msg "$gsu_self $(date): $1"
  56 }
  57 export -f gsu_date_msg
  58
  59 gsu_banner_msg()
  60 {
  61         local txt="*** $gsu_self --"
  62         if test -z "$gsu_banner_txt"; then
  63                 txt="$txt set \$gsu_banner_txt to customize this message"
  64         else
  65                 txt="$txt $gsu_banner_txt"
  66         fi
  67         gsu_short_msg "$txt ***"
  68 }
  69 export -f gsu_banner_msg
  70
  71 gsu_err_msg()
  72 {
  73         local txt="$result" err
  74
  75         gsu_is_a_number "$ret"
  76         if test $ret -lt 0; then
  77                 gsu_msg "unknown error ($ret:$txt)"
  78                 exit 1
  79         fi
  80         if test $result -ge 0; then
  81                 gsu_msg "unknown error ($result:$txt)"
  82                 exit 1
  83         fi
  84         err=$((0 - $result))
  85         if test -n "$txt"; then
  86                 txt="$txt: ${gsu_error_txt[$err]}"
  87         else
  88                 txt="${gsu_error_txt[$err]}"
  89         fi
  90         echo "$gsu_self: $txt" 1>&2
  91 }
  92 export -f gsu_err_msg
  93
  94 gsu_usage()
  95 {
  96         gsu_short_msg "Usage: $gsu_self command [options]"
  97 }
  98 export -f gsu_usage
  99
 100 export gsu_help_txt="
 101 Print online help.
 102
 103 Usage: help [command]
 104
 105 Without arguments, print the list of available commands. Otherwise,
 106 print the help text for the given command."
 107 com_help()
 108 {
 109         local a b
 110         if test -z "$1"; then
 111                 gsu_banner_msg
 112                 gsu_usage
 113                 # sed is magic, baby
 114                 grep -A 2 "^com_\([a-zA-Z_0-9]\+\)()" $0 \
 115                         | grep -v -- '--' \
 116                         | sed -e '/^com_\([a-zA-Z_0-9]\+\)()/bs' \
 117                                 -e 'H;$!d;x;s/\n//g;b' \
 118                                 -e :s \
 119                                 -e 'x;s/\n//g;${p;x;}' \
 120                         | sed -e 's/^com_\([a-zA-Z_0-9]\+\)()#*/\1\t/' \
 121                         | sort \
 122                         | while read a b; do
 123                                 echo -en "$a\t"
 124                                 if test ${#a} -lt 8; then
 125                                         echo -en "\t"
 126                                 fi
 127                                 echo "$b"
 128                         done
 129                 echo
 130                 gsu_msg "Try $0 help <command> for info on <command>."
 131                 ret=$GSU_SUCCESS
 132                 return
 133         fi
 134         if test "$1" = "help"; then
 135                 gsu_short_msg "$gsu_help_txt"
 136                 ret=$GSU_SUCCESS
 137                 return
 138         fi
 139         ret=$GSU_SUCCESS
 140         if grep -q "^com_$1()" $0; then
 141                 sed -e "1,/com_$1()/d" -e '/^{/,$d' -e 's/^## *//' $0
 142                 return
 143         fi
 144         gsu_print_available_commands
 145         result="$1"
 146         ret=-$E_GSU_BAD_COMMAND
 147 }
 148 export -f com_help
 149
 150 gsu_available_commands()
 151 {
 152         result="$( (echo help; grep "^com_[a-z_]\+()" $0) \
 153                 | sed -e 's/^com_//' -e 's/()//' \
 154                 | sort \
 155                 | tr '\n' ' ')"
 156         ret=$SUCCESS
 157 }
 158 export -f gsu_available_commands
 159
 160 gsu_print_available_commands()
 161 {(
 162         local i count
 163         gsu_short_msg "Available commands:"
 164         for i in $gsu_cmds; do
 165                 printf "$i"
 166                 count=$((count + 1))
 167                 if test $((count % 4)) -eq 0; then
 168                         echo
 169                 else
 170                         printf "\t"
 171                         if test ${#i} -lt 8; then
 172                                 printf "\t"
 173                         fi
 174                 fi
 175         done
 176         echo
 177 ) 2>&1
 178 }
 179 export -f gsu_print_available_commands
 180
 181 gsu()
 182 {
 183         gsu_self="$(basename $0)"
 184         gsu_init_errors
 185         gsu_available_commands
 186         gsu_cmds="$result"
 187         if test $# -eq 0; then
 188                 gsu_usage
 189                 gsu_print_available_commands
 190                 exit 1
 191         fi
 192         arg="$1"
 193         shift
 194         for i in $gsu_cmds; do
 195                 if test "$arg" = "$i"; then
 196                         com_$arg $*
 197                         if test $ret -lt 0; then
 198                                 gsu_err_msg
 199                                 exit 1
 200                         fi
 201                         exit 0
 202                 fi
 203         done
 204         ret=-$E_GSU_BAD_COMMAND
 205         result="$arg"
 206         gsu_err_msg
 207         gsu_print_available_commands
 208         exit 1
 209 }
 210 # no need to export this