unzip: 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/unzip - from package: unzip

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

On Debian possible default full paths are:

/usr/bin/unzip - from package: unzip

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

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