vshow: 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/vshow - from package: hdf

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

On Debian possible default full paths are:

/usr/bin/vshow - from package: hdf4-tools

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

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