coverage: 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/coverage - from package: python-coverage

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

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