Hello satyagp.
You can freely delete any log files when you're no longer interested in its content however I would inspect these for the reason of such a huge size first and resolve the root cause of its grow. Alternatively, archiving text files with gzip brings nice results and bzip2 in case of non-binary files is even better (see
gzip --help,
bzip2 --help and
tar --help).
To avoid no disk space issues it is wise to partition your disk appropriately, e.g. separating /boot, /home, /var and maybe other places that you expect to grow quick or consider crucial with mount points located on different disk parts.
Also check
log rotation features and configure your system as you need since it is the best way of learning things.
Are you sure that your logs resides in /dev and not /var directory?
I would also avoid creating stuff on the root and rather do it in /home/user or /opt directories as long as I have no special requirements.
