z80asm: 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 CentOS possible default full paths are:

/usr/bin/z80asm - from package: z80asm

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/z80asm - from package: z80asm

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

Error in other languages:
z80asm: bevel nie gevind nie
z80asm: comandă negăsită
z80asm: comando não encontrado
z80asm: commande introuvable
z80asm: command not found
z80asm: käsku ei ole
z80asm: không tìm thấy lệnh
z80asm: komanda nerasta
z80asm: Kommando nicht gefunden.
z80asm: kommandot finns inte
z80asm: komut yok
z80asm: nie znaleziono polecenia
z80asm: níor aimsíodh an t-ordú
z80asm: no se encontró la orden
z80asm: no s'ha trobat l'ordre
z80asm: opdracht niet gevonden
z80asm: parancs nem található
z80asm: perintah tidak ditemukan
z80asm: príkaz nenájdený
z80asm: příkaz nenalezen
z80asm: команда не найдена
z80asm: командата не е открита
z80asm: 命令找不到
z80asm: コマンドが見つかりません