powerline-lint: 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/powerline-lint - from package: powerline

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

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