pkginfo: 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/pkginfo - from package: python3-pkginfo

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

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