cmark: 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/cmark - from package: cmark

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

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