capitalize: 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/capitalize - from package: xviewg

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

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