#! /bin/sed -f

/../ {

# Reverse a line.  Begin embedding the line between two new-lines
s/^.*$/\
&\
/

# Swap first and last character.  The regexp matches until
# there are zero or one characters between the markers
tx
:x
s/\(\n.\)\(.*\)\(.\n\)/\3\2\1/
tx

# Remove the new-line
s/\n//g
}