travis: command not found

Have You tried accessing the binary with the full path?

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/travis - from package: travis

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