summershum-cli: 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

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/summershum-cli - from package: python-summershum

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