shishi: 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/shishi - from package: shishi

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

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