grid-proxy-destroy: 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/grid-proxy-destroy - from package: globus-proxy-utils

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

On Debian possible default full paths are:

/usr/bin/grid-proxy-destroy - from package: globus-proxy-utils

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

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