filter-langcover: 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/filter-langcover - from package: fontpackages-tools

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

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