sidekiq: 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/sidekiq - from package: ruby-sidekiq

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

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