mcedit: 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/mcedit - from package: mc

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

On Debian possible default full paths are:

/usr/bin/mcedit - from package: mc

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

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