fitcircle: 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/fitcircle - from package: GMT

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

On Debian possible default full paths are:

/usr/lib/gmt/bin/fitcircle - from package: GMT

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

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