fslint-gui: 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/fslint-gui - from package: fslint

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

On Debian possible default full paths are:

/usr/bin/fslint-gui - from package: fslint

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

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