tangle: 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/tangle - from package: texlive

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

On Debian possible default full paths are:

/usr/bin/tangle - from package: texlive-binaries

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

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