squidGuard: 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/squidGuard - from package: squidGuard

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

On Debian possible default full paths are:

/usr/bin/squidGuard - from package: squidGuard

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

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