cppman: 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 Debian possible default full paths are:

/usr/bin/cppman - from package: cppman

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

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