sed s/something/multiple &/ don't get it..

crispyleif · 02-13-2009, 02:02 AM

An example :

"testfile" contains the line "this is a testfile."

#sed -n 's/test/&/p' testfile
#this is a testfile.
#
#sed -n 's/test/& &/p' testfile
#this is a test testfile.
#
#sed -n 's/test/& & &/p' testfile
#this is a test test testfile.

ALL in good order..or understanding at least..

Now :

#echo "test" | sed -n 's/test/&/p'
#test
#
#echo "test" | sed -n 's/test/& &/p'
#test st
#
#echo "test" | sed -n 's/test/& &/p'
#test st st

I don't get it anymore.. and I have tried. I just feel that this is something fundamentally easy, but I can't get my head around it.

colucix · 02-13-2009, 02:17 AM

Really strange, it works as expected for me:

Code:

$ echo "test" | sed -n 's/test/&/p'
test
$ echo "test" | sed -n 's/test/& &/p'
test test
$ echo "test" | sed -n 's/test/& & &/p'
test test test

syg00 · 02-13-2009, 02:48 AM

Gnu ???

colucix · 02-13-2009, 03:24 AM

Non gnu (sed on Solaris 8 2/02 Sparc):

Code:

$ echo "test" | sed -n 's/test/&/p'
test
$ echo "test" | sed -n 's/test/& &/p'
test test
$ echo "test" | sed -n 's/test/& & &/p'
test test test