ldapdiff: 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

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/ldapdiff - from package: ldapdiff

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