test1.bin is the name of my wallet, aka the name i provided when i create it. So user will replace it with his current wallet name.
And "./" stands for current directory im in.
This argument take a filename with his path, so i could use "--wallet-file /home/netmonk/bitmonero/wallet.bin" for exemple, meaning i use the wallet.bin wallet file located in the /home/netmonk/bitmonero/ subdirectory.