comment on

Bash provides roughly 23^3 shortcuts and expansions for searching, editing, and making use of the command history. (Ob-bashmonks-question: 'what's your favorite ReadLine Key Binding?' ... 'Ooh, ooh: C-r' ... 'Heck no, you cretin, real monks only use M-p' ... etc.)

But still, sometimes you need to throw in some Perl. Accordingly, here is a dollop of code that searches through a history list, extracts commands that have been repeated some multiple number of times, and prompts you for aliases to define for those commands.

In typical usage:

source `history | tail -n 400 > /tmp/hist; dynamic-aliases.pl /tmp/his
+t
[download]

But, of course, you don't really want to type all that. So cut and paste, run it a few times (four, unless you change the defaults in the code or on the command line) and you'll be prompted for an appropriate alias. (Note, depending on your environment variable settings, a command run multiple times in a row may only create one entry in your history list. Be warned. And check out the information on HISTCONTROL and friends in the bash man page.)

#!/usr/bin/perl -w
use strict;
$|++;

use Getopt::Long;

## -- DEFAULTS --
my $aliases_file = "/tmp/bash_perl_aliases.sh";
my $hist_size = 400;
my $repeats = 4;
my $min_length = 4;
my $help;
## -- -------- --

GetOptions ( 'repeats=i'    => \$repeats,
             'min_length=i' => \$min_length,
             'help'         => \$help );
usage() if $help;

my @lines = map { m/\d+\s(.*)$/; $1 || ''; } <>;

my %seen; 
my @multiples = sort grep {
  ++$seen{$_} == $repeats and
    length >= $min_length
  } map { /^\s*(.+?)\s*$/ } @lines;

if ( @multiples ) {
  # print numbered "preview" list
  print STDERR 
    'found ' . @multiples . ' repeat' . (@multiples == 1 ? '' : 's') .
+ "\n";
  my $counter = 1;
  foreach ( @multiples ) { print STDERR sprintf "%3d: %s\n", $counter+
++, $_; }
  # prompt for possible alias-ification and write to aliases file
  open ( ALIASES, ">$aliases_file" ) || die "couldn't open outfile: $!
+\n";
  prompt ( @multiples );
  close ( ALIASES );
  print "$aliases_file";
}
print STDERR "\n";
exit ( 0 );

## ------ ##

sub prompt {
  foreach my $command ( @_ ) {
    print STDERR "$command: ";
    my $alias = <>;
    last  if  ! defined $alias; # ctrl-d
    chop $alias;
    print ALIASES "alias $alias='$command'\n"  if  $alias;
  }
}

sub usage {
print STDERR <<END;

source `history | tail -n 400 > /tmp/hist; \
             dynamic-aliases.pl /tmp/hist  [ --repeats <repeats> \ ]
                                           [ --min_length <length> \ ]
                                           [ --help ]`

  This program munges a history list looking for command lines that
  are at least <length> characters long and have been repeated at
  least <repeats> times. If it finds any command lines fitting the
  criteria, it prompts the user for a (presumably shorter) string to
  install as a bash alias for that command. To skip a command line,
  the user may simply hit the new-line key.

  Default values:

  --repeats    $repeats
  --min_length $min_length

  (kwindla\@xymbollab.com)

END
exit ( 0 );
}
[download]

Just starting to come out of my shell,
Kwindla

In reply to bash alias suggest-ation by khkramer

Are you posting in the right place? Check out Where do I post X? to know for sure.
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
Want more info? How to link or How to display code and escape characters are good places to start.


Syntactic Confectionery Delight
	PerlMonks