pick.sh: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/share/doc/mh-book/examples/xmh/bin/pick.sh - from package: mh-book

You may install the required package with command apt-get install {package}

Error in other languages:
pick.sh: bevel nie gevind nie
pick.sh: comandă negăsită
pick.sh: comando não encontrado
pick.sh: commande introuvable
pick.sh: command not found
pick.sh: käsku ei ole
pick.sh: không tìm thấy lệnh
pick.sh: komanda nerasta
pick.sh: Kommando nicht gefunden.
pick.sh: kommandot finns inte
pick.sh: komut yok
pick.sh: nie znaleziono polecenia
pick.sh: níor aimsíodh an t-ordú
pick.sh: no se encontró la orden
pick.sh: no s'ha trobat l'ordre
pick.sh: opdracht niet gevonden
pick.sh: parancs nem található
pick.sh: perintah tidak ditemukan
pick.sh: príkaz nenájdený
pick.sh: příkaz nenalezen
pick.sh: команда не найдена
pick.sh: командата не е открита
pick.sh: 命令找不到
pick.sh: コマンドが見つかりません