bash/bash-utils

   1 #!/bin/bash
   2
   3 pipe()
   4 {
   5         if [ "$1" = --help ]
   6         then
   7                 echo "NAME"
   8                 echo "  pipe - mimic pipe(2) syscall in shell"
   9                 echo "INVOCATION"
  10                 echo "  pipe <READER_VAR> <WRITER_VAR>"
  11                 echo "DESCRIPTION"
  12                 echo "  Create anonymous pipe."
  13                 echo "  Reader end's file descriptor stored in variable name in the first argument."
  14                 echo "  Writer end's file descriptor stored in variable name in the second argument."
  15                 echo "EXAMPLE"
  16                 echo "  pipe read_fd write_fd"
  17                 echo "  echo Lorem ipsum >&\$write_fd"
  18                 echo "  read -u \$read_fd data"
  19                 echo "  echo \$data  # => Lorem ipsum"
  20                 return
  21         fi
  22
  23         local pid1 pid2 myin myout lnk0 lnk1
  24         [ "$1" = rdr ] || local rdr
  25         [ "$2" = wtr ] || local wtr
  26
  27         myin=`readlink /proc/self/fd/0`
  28         myout=`readlink /proc/self/fd/1`
  29
  30         # calling sleep(1) via env to avoid bash's built-in sleep which may not know 'inf'.
  31         env sleep inf | env sleep inf &
  32         pid2=$!
  33         pid1=$(jobs -p %+)
  34
  35         while true
  36         do
  37                 lnk0=`readlink /proc/$pid2/fd/0`
  38                 lnk1=`readlink /proc/$pid1/fd/1`
  39                 if [ "$lnk0" != "$myin" -a "$lnk1" != "$myout" ]
  40                 then
  41                         break
  42                 fi
  43         done
  44
  45         exec {wtr}>/proc/$pid1/fd/1 {rdr}</proc/$pid2/fd/0
  46
  47         disown $pid2
  48         kill -KILL $pid1 $pid2  # sometimes INT and TERM are blocked, but it's safe to kill such a no-op process
  49
  50         eval $1=$rdr
  51         eval $2=$wtr
  52 }
  53
  54 close()
  55 {
  56         if [ "$1" = --help ]
  57         then
  58                 echo "NAME"
  59                 echo "  close - mimic close(2) syscall in shell"
  60                 echo "INVOCATION"
  61                 echo "  close <FD_1> [FD_2 [FD_3 [...]]]"
  62                 echo "DESCRIPTION"
  63                 echo "  Close file descriptor(s) given in arguments."
  64                 echo "EXAMPLE"
  65                 echo "  pipe read_fd write_fd"
  66                 echo "  close \$write_fd"
  67                 return
  68         fi
  69
  70         local fd
  71         for fd in "$@"
  72         do
  73                 #eval "exec $fd>&-"
  74                 exec {fd}>&-
  75         done
  76 }
  77
  78 capture2()
  79 {
  80         if [ "$1" = --help ]
  81         then
  82                 echo "NAME"
  83                 echo "  capture2 - store a command's stdout and stderr in separated variables"
  84                 echo "INVOCATION"
  85                 echo "  capture2 <COMMAND> [<ARGS>]"
  86                 echo "DESCRIPTION"
  87                 echo "  Capture <COMMAND>'s stdout and stderr in separated shell variables"
  88                 echo "  without running it twice."
  89                 echo "  Store stdout and stderr data in script-global variables"
  90                 echo "  called \$capture2_stdout and \$capture2_stderr respectively."
  91                 echo "EXAMPLE"
  92                 echo "  capture2 ls -lRA /etc"
  93                 echo "  echo output was "'\$capture2_stdout'""
  94                 echo "  echo error was "'\$capture2_stderr'""
  95                 echo "RETURN VALUE"
  96                 echo "  <COMMAND>'s exit status"
  97                 echo "VARIABLES"
  98                 echo "  using the following script-global variables"
  99                 echo "  - capture2_stdout"
 100                 echo "  - capture2_stderr"
 101                 echo "CAVEAT"
 102                 echo "  May not work on large output, depend on fifo buffer size."
 103                 echo "SEE ALSO"
 104                 echo "  pipe(1bash) close(1bash)"
 105                 return
 106         fi
 107
 108         local x r w
 109         pipe r w
 110         capture2_stdout=$("$@" 2>&$w)
 111         x=$?
 112         close $w
 113         capture2_stderr=$(cat <&$r)
 114         close $r
 115         return $x
 116 }
 117
 118 is_digit()
 119 {
 120         [ "$1" = 0 -o "$1" = 1 -o "$1" = 2 -o "$1" = 3 -o "$1" = 4 -o "$1" = 5 -o "$1" = 6 -o "$1" = 7 -o "$1" = 8 -o "$1" = 9 ]
 121 }
 122
 123 is_number()
 124 {
 125         [ "$1" -ge 0 -o "$1" -lt 0 ] 2>/dev/null
 126 }
 127
 128 is_alpha()
 129 {
 130         expr "$1" : '[a-zA-Z]\+$' >/dev/null 2>&1
 131 }
 132
 133 warnx()
 134 {
 135         true "warnx - mimic warnx(3) in shell"
 136         echo "${0##*/}: $*" >&2
 137 }
 138
 139 errx()
 140 {
 141         true "errx - mimic errx(3) in shell"
 142         errno=$1
 143         shift
 144         warnx "$@"
 145         exit $errno
 146 }
 147
 148 bash_isset()
 149 {
 150         local sets=${2:-$-}
 151         sets=${sets//[!$1]/}
 152         echo ${sets:-_}
 153 }
 154
 155 bash_defined()
 156 {
 157         [ "${!1+x}" = x ]
 158 }
 159
 160 bash_trapbody()
 161 {
 162         local a
 163         a=`trap -p "$1"`
 164         if [ -z "$a" ]
 165         then
 166                 echo -
 167                 return
 168         fi
 169         a=${a:9}
 170         a=${a:0:-${#1}-2}
 171         echo "$a"
 172 }
 173
 174 try()
 175 {
 176         declare -g TRYSTACK
 177         local savesets=$-
 178         TRYSTACK+=($(bash_isset e $savesets)$(bash_isset E $savesets)"$(bash_trapbody ERR)")
 179         trap - ERR
 180
 181         while [ -n "$1" ]
 182         do
 183                 case "$1" in
 184                 --except)
 185                         shift
 186                         trap "$1" ERR
 187                         ;;
 188                 *)
 189                         echo "Unknown option: $1" >&2
 190                         set -o errexit
 191                         false
 192                         ;;
 193                 esac
 194                 shift
 195         done
 196
 197         set -o errexit
 198         set -o errtrace
 199 }
 200
 201 untry()
 202 {
 203         local trydata
 204         trydata=${TRYSTACK[-1]}
 205         unset TRYSTACK[${#TRYSTACK[@]}-1]
 206         [ "${trydata:0:1}" = _ ] && set +o errexit || set -o errexit
 207         [ "${trydata:1:1}" = _ ] && set +o errtrace || set -o errtrace
 208         trap "${trydata:2}" ERR
 209         return 0
 210 }
 211
 212 fixerrexit()
 213 {
 214         ( eval "expr '$-' : '.*e' >/dev/null && set -e; $*"; )
 215 }
 216
 217 template()
 218 {
 219         cat "$@" |\
 220         {
 221                 local rline tvar var replace sedexpr
 222                 while read -r
 223                 do
 224                         rline=$REPLY
 225                         sedexpr=""
 226                         { grep -Eo '%[a-zA-Z0-9\./_-]+%' <<<"$rline" || true; } |\
 227                         sort -u |\
 228                         {
 229                                 while read tvar
 230                                 do
 231                                         # strip percent marks
 232                                         var=${tvar:1:-1}
 233                                         # resolve bash variable
 234                                         replace=${!var}
 235                                         # avoid backrefs
 236                                         replace=${replace//\\/\\\\}
 237                                         # avoid whole match backref
 238                                         replace=${replace//&/\\&}
 239                                         # compose sed expression like: s@%user\.name%@joe@g;s@%user\.email%@joe\@local@g;
 240                                         sedexpr="${sedexpr}s@${tvar//\./\\.}@${replace//@/\@}@g;"
 241                                 done
 242                                 # action
 243                                 sed -e "$sedexpr" <<<"$rline"
 244                         }
 245                 done
 246         }
 247 }
 248
 249 errorlevel()
 250 {
 251         return $1
 252 }
 253
 254 bash_join()
 255 {
 256         local IFS=$1
 257         shift
 258         echo "$*"
 259 }
 260
 261 in_list()
 262 {
 263         local needle=$1
 264         local hay
 265         shift
 266         for hay in "$@"
 267         do
 268                 if [ ".$hay" = ".$needle" ]
 269                 then
 270                         return 0
 271                 fi
 272         done
 273         return 1
 274 }
 275
 276 array_shift()
 277 {
 278         if [ "$1" = --help ]
 279         then
 280                 echo "NAME"
 281                 echo "  array_shift - print and remove the first element from a bash indexed array"
 282                 echo "INVOCATION"
 283                 echo "  array_shift <VARNAME>"
 284                 echo "EXAMPLE"
 285                 echo "  shoplist=(bread milk sausage)"
 286                 echo "  first_element=\$(array_shift shoplist)"
 287                 echo "  next_element=\$(array_shift shoplist)"
 288                 return
 289         fi
 290
 291         local array_name=$1
 292         local aux
 293         eval "aux=\${$array_name[0]}"
 294         unset $array_name[0]
 295         eval "$array_name=(\"\${$array_name[@]}\")"
 296         echo "$aux"
 297 }
 298
 299 array_reverse()
 300 {
 301         if [ "$1" = --help ]
 302         then
 303                 echo "NAME"
 304                 echo "  array_reverse - reverse the order of elements in a bash array in-place"
 305                 echo "INVOCATION"
 306                 echo "  array_reverse <VARNAME>"
 307                 echo "RETURN VALUE"
 308                 echo "  void"
 309                 return
 310         fi
 311
 312         local array_name=$1
 313         local i ci len aux
 314         eval "len=\${#$array_name[@]}"
 315         for ((i=0; i<len/2; i++))
 316         do
 317                 ci=$[len-i-1]
 318                 eval "aux=\${$array_name[$i]}"
 319                 eval "$array_name[$i]=\${$array_name[$ci]}"
 320                 eval "$array_name[$ci]=\$aux"
 321         done
 322 }
 323
 324 bash_scriptdir()
 325 {
 326         dirname "$(readlink -f "${BASH_SOURCE[-1]}")"
 327 }
 328
 329 ECHO()
 330 {
 331         printf %s "$*"
 332 }
 333
 334 canonize_semver()
 335 {
 336         # return the canonical form of a version string
 337         local ver=$1
 338         # trailing ".0" is considered meaningless by SemVer
 339         while [[ $ver =~ ^(.+)\.0+$ ]]
 340         do
 341                 ver=$${BASH_REMATCH[1]}
 342         done
 343         echo "$ver"
 344 }
 345
 346 version_compare()
 347 {
 348         # take 2 version numbers (as strings) in arguments, say A and B.
 349         # return
 350         #   0 when A equals to B,
 351         #   1 when A is greater than B, or
 352         #   255 (ie. -1) when A is less than B.
 353         local ver_a=$1
 354         local ver_b=$2
 355         ver_a=`canonize_semver "$ver_a"`
 356         ver_b=`canonize_semver "$ver_b"`
 357         if [ "$ver_a" = "$ver_b" ]
 358         then
 359                 return 0
 360         fi
 361         # feed the 2 version numbers, 1 per line, to sort, then take the first line, which will be the lesser one.
 362         local lesser_version=`echo "$ver_a"$'\n'"$ver_b" | sort --version-sort | sed -ne 1p`
 363         if [ "$ver_a" = "$lesser_version" ]
 364         then
 365                 return 255
 366         else
 367                 return 1
 368         fi
 369 }
 370
 371 version_is_lesser()
 372 {
 373         version_compare "$1" "$2"
 374         if [ $? = 255 ]
 375         then
 376                 return 0
 377         else
 378                 return 1
 379         fi
 380 }
 381
 382 version_is_greater()
 383 {
 384         version_compare "$1" "$2"
 385         if [ $? = 1 ]
 386         then
 387                 return 0
 388         else
 389                 return 1
 390         fi
 391 }
 392
 393 version_is_greater_or_equal()
 394 {
 395         ! version_is_lesser "$@"
 396 }
 397
 398 version_is_lesser_or_equal()
 399 {
 400         ! version_is_greater "$@"
 401 }