How do I resize root partition

I need to resize root as there is not enough space left in the partition. At present I am not able to install new package nor update ubuntu. I tried sudo apt-get clean and emptying trash but it does not make significant space.

I have dual boot system (windows-7 and Ubuntu 14.04 LTS) with two Internal hard drive. Where Windows is installed in /dev/sda and Ubuntu is installed in /dev/sdb. I tried to resize root using Gparted but it does not allow. Please let me know the steps of using Gparted for resizing root. I want to transfer space from "/home" to "/".

df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/sdb5        14G   13G  271M  98% /
none            4.0K     0  4.0K   0% /sys/fs/cgroup
udev            3.8G  8.0K  3.8G   1% /dev
tmpfs           779M  1.3M  777M   1% /run
none            5.0M     0  5.0M   0% /run/lock
none            3.8G  160K  3.8G   1% /run/shm
none            100M   56K  100M   1% /run/user
/dev/sdb1       3.7G  555M  2.9G  16% /boot
/dev/sdb7       896G   75G  776G   9% /home

--

sudo fdisk -l
Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x38696756
Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048      206847      102400    7  HPFS/NTFS/exFAT
/dev/sda2          206848   976771071   488282112    7  HPFS/NTFS/exFAT
Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x000a1848
Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *        2048     7852031     3924992   83  Linux
/dev/sdb2         7854078  1953523711   972834817    5  Extended
Partition 2 does not start on physical sector boundary.
/dev/sdb5         7854080    37148671    14647296   83  Linux
/dev/sdb6        37150720    45043711     3946496   82  Linux swap / Solaris
/dev/sdb7        45045760  1953523711   954238976   83  Linux

Thank you


You do not have /root partition. You probably want to increase size of your / partition.

You will have to boot from liveCD to resize these partitions.

It must be safe, because you have a separate /boot partition, otherwise /etc/fstab may need to be updated with new UUID and/or grub reinstalled.

In your case you need to shrink your /home, which is /dev/sdb7, then move your swap partition right, then extend your / (/dev/sdb5) right.

You can do it with a mouse. Just drag partition's sides left or right.

This may take a lot of time.