sextractor: 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/sextractor - from package: sextractor

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

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