cat blah | nl -w10 | sort -k2 | uniq -f1 | sort -nk1 | cut -sf2-

export HISTCONTROL=erasedups

export HISTIGNORE="&:mc:top:exit:mplayer *"

package main

import (
    "os"
    "bufio"
)

func read_strs() []string {
    var strs []string
    r := bufio.NewReader(os.Stdin)
    str, err := r.ReadString('\n')
    for err != os.EOF {
        strs = append(strs, str)
        str, err = r.ReadString('\n')
    }
    return strs
}

func write_uniq(strs []string) {
    w := bufio.NewWriter(os.Stdout)
    for i, s := range strs {
        j := i + 1
        for j < len(strs) && strs[j] != s {
            j++
        }
        if j >= len(strs) {
            w.WriteString(s)
        }
    }
    w.Flush()
}

func main() {
    strs := read_strs()
    write_uniq(strs)
}

cat .bash_history | perl -e 'my %hash = (); while(<>){ print and $hash{$_} = "" if not defined $hash{$_} };'

module H = Hashtbl
module L = List

let tbl_add tbl line n =
  try let _ = H.find tbl line in () with Not_found -> H.add tbl line n

let rec collect_lines n tbl =
  try let line = input_line stdin in
      tbl_add tbl line n; collect_lines (n+1) tbl
  with End_of_file -> tbl

let unique_lines () =
  let to_list tbl = H.fold (fun k v l -> (k,v)::l) tbl [] in
  to_list (collect_lines 1 (H.create 50000))

let sort_by_number = L.sort (fun (k1,v1) (k2,v2) -> v1-v2)

let output = L.iter (fun (l,_) -> output_string stdout (l ^ "\n"))

let _ = output (sort_by_number (unique_lines ()))

package main

import (
    "os"
    "bufio"
)

type mapstr map[string]int

func read_strs() (strs []string) {
    r := bufio.NewReader(os.Stdin)
    str, err := r.ReadString('\n')
    for err != os.EOF {
        strs = append(strs, str)
        str, err = r.ReadString('\n')
    }
    return
}

func write_strs(strs []string) {
    w := bufio.NewWriter(os.Stdout)
    for _, s := range strs {
        w.WriteString(s)
    }
    w.Flush()
}

func uniq(strs []string) []string {
    m := make(map[string] int, 50000)
    k := len(strs) - 1
    for i := k; i >= 0; i-- {
        _, ok := m[strs[i]]
        if !ok {
            m[strs[i]] = k
            k--
        }
    }
    uniq_strs := make([]string, len(m))
    for s, i := range m {
        uniq_strs[i - k - 1] = s
    }
    return uniq_strs
}

func main() {
    strs := read_strs()
    write_strs(uniq(strs))
}

module L = List
module S = Set.Make(struct type t = string let compare = compare end)

let unique_lines () =
  let rec loop set lst =
    try let line = input_line stdin in
        if S.mem line set
        then loop set lst
        else loop (S.add line set) (line::lst)
    with End_of_file -> lst
  in L.rev (loop S.empty [])

let _ = L.iter (fun l -> output_string stdout (l ^ "\n")) (unique_lines())

let tbl_add tbl line n =
  try let _ = H.find tbl line in () with Not_found -> H.add tbl line n

H.replace tbl line n

tac hist1 | nl -w10 | sort -k2 | uniq -f1 | sort -nk1 | cut -sf2- | tac > hist2

tac hist1 | nl -w10 | sort -s -k2 | uniq -f1 | sort -nk1 | cut -sf2- | tac > hist2

let yobaDistinct = Seq.mapi (curry id) >> Seq.distinctBy snd >>  Seq.sortBy fst >> Seq.map snd