squidclient: 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/squidclient - from package: squid34
/usr/bin/squidclient - from package: squid

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

On Debian possible default full paths are:

/usr/bin/squidclient - from package: squidclient
/usr/lib/debug/usr/bin/squidclient - from package: squid3-dbg

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