hgview: command not found

Have You tried accessing the binary with the full path?

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 Debian possible default full paths are:

/usr/bin/hgview - from package: hgview-common

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