unetbootin not detecting pen drive device id in drop down

Run command

unetbootin installtype=USB targetdrive=/dev/sdb1

grub rescue error

grub rescue error : unknown filesystem

If you have tried following commands and still you are getting grub rescue error.

ls
ls (hd0,msdosx)/ #where x is the number depends on ls output.In this case,it is 6
set prefix=(hd0,6)/boot/grub
set root=(hd0,6)
insmod normal
normal

If insmod normal command is not working and showing unknown file system error.

Solution :
Boot your linux with pendrive or cd/dvd.
Select option "Run without installing". Now you can open terminal.
You need to scan the filesystem to resolve errors. Run command

sudo fsck /dev/sda1

where /dev/sda1 is the root partition of your hard disk.

Once it scans and checks complete filesystem, reboot your system.
You will not end up with grub rescue error.

/var/tmp/mongo/contrib/php-ssl.h:33:25: error: openssl/evp.h: No such file or directory

Compilation error : mongo compilation error :
/var/tmp/mongo/contrib/php-ssl.h:33:25: error: openssl/evp.h: No such file or directory

Solution :

You need to install package openssl-devel

Run following command on Centos/Fedora/RHEL

yum install openssl-devel

Now try to compile your package again, you will not get this error.