Synax: /checkdoubles
What this does: It will check every line of a text file and if two lines match, it will remove one.

alias checkdoubles {
  set %lcv.chkdbl 1
  while (%lcv.chkdbl <= $lines($1-)) {
    hadd -m chkdbl $read($1-,%lcv.chkdbl) 1
    inc %lcv.chkdbl
  }
  set %lcv.chkdbl 1
  write -c " $+ $1- $+ "
  while (%lcv.chkdbl <= $hget(chkdbl,0).data) {
    write " $+ $1- $+ " $hget(chkdbl,%lcv.chkdbl).item
    inc %lcv.chkdbl
  }
  unset %lcv.chkdbl
  hfree chkdbl
}