rootninja

Change lowercase to uppercase or vice versa using sed

The brute force easy way:

sed ‘y/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/’`

That works, but it’s a lot of typing.

The smart way:

’s/./\u&/g’

This matches any character and replaces it with the uppercase version of that character, and does it globally. Does it get any simpler than that?

One use of this would be finding the hardware address of an interface and converting it to all uppercase.

$ cat /sys/class/net/eth0/address
00:11:de:ad:be:ef

$ cat /sys/class/net/eth0/address | sed ’s/.\/u&/g’
00:11:DE:AD:BE:EF