fc-scan: 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/fc-scan - from package: fontconfig

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

On Debian possible default full paths are:

/usr/bin/fc-scan - from package: fontconfig

You may install the required package with command apt-get install {package}

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