memtouch: 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 CentOS possible default full paths are:

/usr/bin/memtouch - from package: libmemcached10

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