I forgot what was wifi setting of my respberry -3. I want to connect that, but my device is not connecting to the wifi. Is there any way I can change the wifi setting of my device. I am able to mount the flash of my device on linux.
To summarize the suggestions from the comments, you wrote:
I am able to mount the flash of my device on linux.
You do not tell us what Operating System you are using so I assume it is Raspbian. This OS is installed on two partitions: the first partition is labeled boot and is formated as
vfat, the second partition is labeled rootfs and is formated as
ext4. You can show it with:
rpi ~$ sudo blkid
The linux OS you are using is able to read
ext4 file systems so you can mount the second partition with (if for example the SD Card is attached to /dev/sdb):
rpi ~$ mkdir rootfs/ rpi ~$ sudo mount /dev/sdb2 rootfs/
Now you can access
rootfs/etc/wpa_supplicant/wpa_supplicant.conf and modify it as @goldilocks suggested in his answer. If you have done, finish with:
rpi ~$ sudo umount rootfs/ rpi ~$ rmdir rootfs/
and boot the SD Card with your RasPi.