unsq: 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/bin/unsq - from package: ispell

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

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