qmlmin: 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/qmlmin - from package: qt5-qtdeclarative-devel
/usr/lib64/qt5/bin/qmlmin - from package: qt5-qtdeclarative-devel
/usr/lib/qt5/bin/qmlmin - from package: qt5-qtdeclarative-devel

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

On Debian possible default full paths are:

/usr/bin/qmlmin - from package: qtchooser
/usr/lib/x86_64-linux-gnu/qt5/bin/qmlmin - from package: qtdeclarative5-dev-tools

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

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