Hi,
I can't seem to understand what the sed and & do.. Why is the set of numbers appear twice ? how the command really work ?
echo "123 abc" | sed 's/[0-9]*/& www &/'
Output:
123 www 123 abc
Hi,
I can't seem to understand what the sed and & do.. Why is the set of numbers appear twice ? how the command really work ?
echo "123 abc" | sed 's/[0-9]*/& www &/'
Output:
123 www 123 abc
man sed
yields:
s/regexp/replacement/
Attempt to match regexp against the pattern space. If success
ful, replace that portion matched with replacement. The
replacement may contain the special character & to refer to that
portion of the pattern space which matched, and the special
escapes \1 through \9 to refer to the corresponding matching
sub-expressions in the regexp.
I understood the supposed function of sed with &, but this explanation (I read something similar before posting) doesn't explain to me why the set of numbers appears twice, and how the output came to be this way..
the numbers appear twice because there're 2 &-s separated by www.
echo "123 abc" | sed 's/[0-9]*/& www &/'