untrigraph: 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/untrigraph - from package: liwc

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

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