sdrinfo: 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/sdrinfo - from package: Pixie

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

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