flarq: 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 CentOS possible default full paths are:

/usr/bin/flarq - from package: fldigi

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

On Debian possible default full paths are:

/usr/bin/flarq - from package: fldigi

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