How to move a partition in GNU/Linux?

Manual way with dd and fdisk:

# fdisk -l /dev/sdb | grep sdb3
/dev/sdb3        73402368  1953525167   940061400   83  Linux

# fdisk /dev/sdb
Command (m for help): d
Partition number (1-4): 3
Command (m for help): n
Partition number (1-4, default 3): 3
First sector (73385984-1953525167, default 73385984): 
Using default value 73385984
Last sector, +sectors or +size{K,M,G} (73385984-1953525167, default 1953525167): 
Using default value 1953525167
Command (m for help): w
The partition table has been altered!

# fdisk -l /dev/sdb | grep sdb3
/dev/sdb3        73385984  1953525167   940069592   83  Linux

# dd conv=notrunc bs=512 iflag=fullblock if=/dev/sdb3 count=100 skip=$((73402368-73385984)) seek=0 2> /dev/null | file -s -
/dev/stdin: LUKS encrypted file, ver 1 [aes, cbc-essiv:sha256, sha1] UUID: af1c47f0-4ca5-4ea7-a091-065bd263653f

# dd conv=notrunc bs=512 iflag=fullblock if=/dev/sdb3  skip=$((73402368-73385984)) seek=0 of=/dev/sdb3

# file -s /dev/sdb3
/dev/sdb3: sticky LUKS encrypted file, ver 1 [aes, cbc-essiv:sha256, sha1] UUID: af1c47f0-4ca5-4ea7-a091-065bd263653f

Now waiting for about 2h. (more looks more like 18h...)

Note: this only moves data back, not forward.

Pausing:

# pidof dd
907
# kill -STOP 907
# cat /proc/907/fdinfo/1
pos:    586921398272
flags:  0100001

# kill -9 907

remember 586921398272/512 = 1146330856

Resuming:

dd conv=notrunc bs=512 iflag=fullblock if=/dev/sdb3  skip=$((1146330856+73402368-73385984)) seek=1146330856 of=/dev/sdb3

sfdisk, which intents to be a scriptable fdisk, has since some version the --move-data option. Example from their man page:

echo '+100M,' | sfdisk --move-data /dev/sdc -N 1

You can always use dd.

• Boot from a liveCD (or any other way which makes sure the partition is not mounted)
• dd if=/dev/sdc2 of=somefile bs=1M to create a copy of the partition on a file.
• fdisk (or whatever you like) to delete the partition
• fdisk (or whatever you like) to create the partition in your desired place.
• dd of=/dev/sdc2 if=somefile bs=1M to restore the contents from file.