srf_extract_linear: 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 Debian possible default full paths are:

/usr/bin/srf_extract_linear - from package: staden-io-lib-utils

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

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