unifuzz: command not found

Have You tried accessing the binary with the full path?

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/unifuzz - from package: uniutils

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