Greetings, Eliot Moss! >>> I encounter some problem with grep option -E on cygwin 3.0.7 >> >> >>> echo "a^b" | grep "a^b" #answer a^b ie it's OK >>> but >>> echo "a^b" | grep -E "a^b" #answer nothing " for me it's KO >> >> That's an expected result of an impossible constraint. >> >>> I have to backslash ^ to be OK like : grep -E 'a\^b' >> >> Yes. >> >>> Is-it a bug ? >> >> No. >> >>> I don't know if all versions of cygwin and grep are concerned. >> >> RTFM, this is regexp basics.
> There was a really great answer to this earlier. I tried an > answer, but was wrong. One has to read the "fine print" really > carefully. At first I thought it was a bug, at least in the > documentation, but the meaning of a^b, when ^ is the metacharacter, > is kind of subtle (IMO at least). It's easy to miss that > subtlety and think that if ^ is not at the beginning of an > expression it will be treated as an ordinary character ... > But my main point is that RTM would be enough; RTFM seemed > to me perhaps a little more rude than necessary. Adding to the earlier answers (sorry, replying on the road is not efficient), there's a https://www.regular-expressions.info/ Which contains a great deal of information about RE, their kinds, caveats and implementations in various languages. -- With best regards, Andrey Repin Friday, August 30, 2019 10:42:35 Sorry for my terrible english... -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
