cgclear: 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:

/sbin/cgclear - from package: libcgroup

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

On Debian possible default full paths are:

/usr/sbin/cgclear - from package: cgroup-tools

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

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