texmaker: 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/texmaker - from package: texmaker

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

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