bash/command-not-found-handle.sh

   1 #!/bin/bash
   2
   3 command_not_found_handle()
   4 {
   5         local badcmd=$1
   6         #shift
   7         #declare -a args=("$@")
   8
   9         echo "$badcmd: command not found. similar commands: " >&2
  10
  11         local distance_threshold
  12         if [ ${#badcmd} -le 4 ]
  13         then
  14                 distance_threshold=1
  15         else
  16                 distance_threshold=2
  17         fi
  18         local startswith_threshold=3
  19         local endswith_threshold=0
  20         local min_suggestions=20
  21
  22         # 1. list every commands in all the PATH directories and bash functions
  23         #    and aliases.
  24         # 2. measure Levenshtein between the typed word and each commands.
  25         # 3. find exact matches of typed word in each commands and score them
  26         #    according to how close is it to the start or end of the command name.
  27         # 4. calc the lowest score (the lower the better), ie. overall score.
  28         # 5. sort the commands first by the lowest score, then length.
  29         # 6. pass through commands, scores of which are below threshold.
  30         # 7. worse-score commands are passed through too, in groups, to show at
  31         #    least a given number of suggestions.
  32         #    they are groupd by the overall score.
  33
  34         {
  35                 find ${PATH//:/ } -maxdepth 1 -type f -executable -printf '%f\n' 2>/dev/null
  36                 declare -p -F | cut -d' ' -f3-
  37                 alias -p | cut -d' ' -f2- | cut -d= -f1
  38         }\
  39         | levenshtein-distance "$badcmd" \
  40         | env badcmd=$badcmd perl -ne '
  41                 BEGIN {
  42                         use List::Util qw/min/;
  43                         $\ = "\n";
  44                         $, = "\t";
  45                         $worst_score = 999;
  46                 }
  47                 chomp;
  48                 s/^(\d+)\s//;
  49                 $distance = $1;
  50                 $len = length;
  51                 $spos = index $_,  $ENV{badcmd}; $spos = $worst_score if $spos == -1;
  52                 $rpos = rindex $_, $ENV{badcmd};
  53                         if($rpos == -1) { $epos = $worst_score; } else { $epos = $len - ($rpos + length($ENV{badcmd})); }
  54                 print min($spos, $epos, $distance), $spos, $epos, $distance, $len, $_;' \
  55         | sort -k1n -k5n \
  56         | env min_suggestions=$min_suggestions startswith_threshold=$startswith_threshold endswith_threshold=$endswith_threshold distance_threshold=$distance_threshold\
  57                 perl -ne '
  58                 $, = "\t";
  59                 s/(\S+)\s(\S+)\s(\S+)\s(\S+)\s(\S+)\s//;
  60                 ($score, $spos, $epos, $distance, $len) = ($1, $2, $3, $4, $5);
  61                 if($spos > $ENV{startswith_threshold} and $epos > $ENV{endswith_threshold} and $distance > $ENV{distance_threshold})
  62                 {
  63                         if($printed >= $ENV{min_suggestions} and $score ne $last_score) { exit; }
  64                 }
  65                 print "$_";
  66                 $printed++;
  67                 $last_score = $score;' \
  68         | column \
  69           >&2
  70
  71         return 127
  72 }