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gwhence

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  1. #!/bin/zsh
  2. #
  3. # gwhence - generic version of builtin "whence" that works on a user-
  4. # specifiable path.
  5. #
  6. # usage:
  7. # gwhence [-a] [-m] [-s path] name . . .
  8. #
  9. # where
  10. # -a causes all matching names to be printed, not just the first
  11. # one that occurs in the path.
  12. # -m allows name(s) to be shell patterns (implies -a)
  13. # -s lets you supply a colon-separated path for gwhence to
  14. # search for name(s) (default is $PATH)
  15. #
  17. local opt elem names found all pattern ng
  19. local usage="Usage: $0:t [-am] [-s path] name . . ."
  21. # no arguments - return with zero exit status
  22. if [[ $# -eq 0 ]]
  23. then
  24. return 0
  25. fi
  27. # search path defaults to $PATH
  28. local search="$PATH"
  30. # fetch options
  31. while getopts :ams: opt
  32. do
  33. case "$opt" in
  34. 'a') all=true ;;
  35. 'm') pattern=true ;;
  36. 's') search="$OPTARG" ;;
  37. ':') [[ "$OPTARG" = 's' ]] && echo "$usage" ;;
  38. '?') echo "$usage" ; return 1 ;;
  39. esac
  40. done
  42. # put options behind us
  43. shift $[ $OPTIND - 1 ]
  45. # remember state of nullglob
  46. [[ -o nullglob ]] && ng=true
  47. setopt nullglob
  49. # if none found, must report it by nonzero exit status at end
  50. found=
  52. # for each name supplied . . .
  53. for names
  54. do
  55. # scan path, in pieces (colon is separator)
  56. for elem in ${(s/:/)=search}
  57. do
  58. # pattern matching (-m)
  59. if [[ "$pattern" = "true" ]]
  60. then
  61. # for compatibility with whence, must put next line here, not inside
  62. # following if construct
  63. found=true
  64. if [[ -n "$(eval 'echo -n $elem/'$names'')" ]]
  65. then
  66. # Must output them on separate lines
  67. eval 'echo $elem/'$names' | tr '\'' '\'' '\''\n'\'
  68. fi
  69. else
  70. if [[ -a $elem/$names ]]
  71. then
  72. echo $elem/$names
  73. # we found one - remember it
  74. found=true
  75. fi
  76. # note that "found" only applies if -m was not specified
  77. if [[ "$found" = "true" && "$all" != "true" ]]
  78. then
  79. break
  80. fi
  81. fi
  82. done
  83. done
  85. # reset nullglob status
  86. [[ "$ng" = "true" ]] || unsetopt nullglob
  88. # a name not found?
  89. if [[ "$found" != "true" ]]
  90. then
  91. return 1
  92. fi
  93. # exit safely
  94. return 0