capinfos: 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/sbin/capinfos - from package: wireshark

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

On Debian possible default full paths are:

/usr/bin/capinfos - from package: wireshark-common

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

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