bug#19414: bug in sed

[Buchs, Kevin J.]

I am using sed, version 4.2.1 on a few different systems. What I have 
discovered is that inside a substitute command, a space alone is 
magically anchored at the start of the line in an anti-greedy match.

As an example, consider this input stream:

 a                     <-- leading space
b c
d  e
f    g


Along with these one-liner invocations:

sed -e 's/ *//'
sed -e 's/[ ]*//'
sed -e 's/[[:space::]]*//'
sed -e 's/ ?//'
sed -e 's/ +//'

What seems to be happening is that the wildcard match gets anchored to 
the beginning of the line with a zero character hit.

This case seems to apply not only to spaces but other characters.

--
Kevin Buchs   Research Computer Services   Phone: 507-538-5459
Mayo Clinic   200 1st. St SW   Rochester, MN 55905   http://mayoclinic.org