for example i have the file that contain several line..and i want to swap the first word and the second word than i store it into new file..

on the command i wrote:

sed -e "s/^\([^]*\)\([^]*\)/\2\1/g" file > swapfile

sed: -e expression #1, char 26:invalid reference \2 on 's' command's RHS

actually i already solve it using awk ..

but i am still curious for the sed command...i think we can do it also using sed comand right?

sed 's/^\([^ ][^ ]*\) \([^ ][^ ]*\)/\2 \1/' file > swapfile

^^
Thanks for the reply..

unfortunately that code doesnt work also..the code only swap the last letter in the word to the front of the word...

let me find it out....

Are you sure?

reborg@www:~$ cat file
one two three four five
one two three four five
one two three four five
one two three four five
one two three four five
one two three four five
reborg@www:~$ sed 's/^\([^ ][^ ]*\) \([^ ][^ ]*\)/\2 \1/' file
two one three four five
two one three four five
two one three four five
two one three four five
two one three four five
two one three four five
reborg@www:~$

oh mate...

sorry...it is working...i just miss the [space] there....

thanks...