placeholder: 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/lib/golang/misc/nacl/testdata/bin/placeholder - from package: golang-misc

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

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