pgmedge: 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/pgmedge - from package: netpbm-progs

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

On Debian possible default full paths are:

/usr/bin/pgmedge - from package: netpbm

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

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