mendex: 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/mendex - from package: mendexk

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

On Debian possible default full paths are:

/usr/bin/mendex - from package: mendexk
/usr/bin/mendex - from package: texlive-binaries

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

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