SYNOPSIS
    From script:
     use Bash::History::Read qw(parse_bash_history_file);
     
     my $res = parse_bash_history_file("$ENV{HOME}/.bash_history");
    Sample result:
     [
       [undef, "some-command\n"],
       [1446715184, "du -sm\n"],
       [1446715190, "ls -l\n"],
     ]
    From the command-line:
     % perl -MBash::History::Read -i.bak -e'each_hist {
           $PRINT = 0 if $TS < time()-2*30*86400; # delete old entries
           $PRINT = 0 if /foo/; # delete unwanted lines (e.g. matching some regex)
           s/(mysql\s+-p)(\S+)/$1******/; # redact sensitive information
       }' ~/.bash_history
DESCRIPTION
    This module provides utility routines to read entries from bash history
    file (by default ~/.bash_history). The format of the history file is
    dead simple: one line per entry, but when HISTTIMEFORMAT environment is
    set, bash will print a timestamp line before each entry, e.g.:
     #1374290613
     ls -al
     #1374290618
     less myfile
     #1374290635
     ...
    See each_hist for one routine to let you handle this format
    conveniently.
FUNCTIONS
 parse_bash_history_file([ $path ]) => array
    Parse entries from bash history file. If unspecified, $path will
    default to HISTFILE environment variable or $HOME/.bash_history.
    Return an array of entries, where each entry is <[$timestamp, $line]>
    and $timestamp can be undef if entry does not have a timestamp.
 each_hist { PERL_CODE }
    Will read lines from the diamond operator (<>) and call Perl code for
    each history entry. Can handle timestamp lines. This routine is
    exported by default and is meant to be used from one-liners.
    Inside the Perl code, $_ is locally set to the entry content, $TS is
    locally set to the timestamp (and changes to this variable is ignored,
    except when you undefine the variable, which will remove the timestamp
    from output), $PRINT is locally set to 1. If $PRINT is still true by
    the time the Perl code ends, the entry (along with its timestamp) will
    be printed. So to remove a line, you can set $PRINT to 0 in your code.
    To modify content, modify the $_ variable.