compress: 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/compress - from package: ncompress

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

On Debian possible default full paths are:

/usr/bin/compress - from package: ncompress

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

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