Case insensivite regular expression for bash shell on mac

Question

I am trying to get a case insensitive word match for a bash shell on a mac.

I try:

echo "one Word" | grep -e "\bword\b/i"

and

 echo "one Word" | grep -e "(?i)\bword\b"

But no luck. Any ideas?

Answer 1

grep的-i选项用于忽略大小写：

echo "one Word" | grep -i "\bword\b"

Answer 2

What you are trying to do looks perlish. With GNU grep, you can do this:

echo "one Word" | grep -P "(?i)\\bword\\b"

...although clearly the -i switch is the standard way to do this.