clipaccumulate: 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/clipaccumulate - from package: perl-Clipboard

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

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