-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Willie Wong wrote:
>On Sun, Nov 06, 2005 at 09:03:01PM -0800, gentuxx wrote: > >>sed -n '/^CLOCK=/s/^\(CLOCK=".*"\).*$/\1/p /etc/conf.d/clock >> > >Ah, yes, I misunderstood the OP. I thought he didn't want the lines >with trailing comments at all. > He didn't really make that clear in his first post. ;-) >But is it necessary to give the address for an s// replacement? As I >understand it that sed is a stream editor and will try the replacement >on every "line" it encounters. The -n flag would guarantee only the >line changed would be printed anyway. > No, the address is NOT necessary for this case. I stated that in my reply to his post. However, sed will only replace the first instance found, unless the 'g' flag is specified ( s///g ). Then it'll search and replace globally. The '-n' option suppresses unchanged output, so if the output of the sed command was being redirected to a file, only the changed lines would be printed. So, in this case, you would NOT want to use the '-n' option, because you would want the entire file output *with* the changes. >I guess what I am saying is that > sed -n 's/^\(CLOCK=".*"\).*$/\1/p' /etc/conf.d/clock >would do just as fine, no? > >W (See above). To actually make changes to the file, once you had tested your regular expressions to STDOUT, you would most likely want to redirect it to a file to replace the original file. If you include the '-n' option, all of the unchanged lines would not be printed or redirected - so you would have your changes, but nothing else. So for your final "run", you would want something without the '-n' option. And without the '-n' option, the print command ( s///p ) is moot. (See my most recent reply to the OP for a final solution.) - -- gentux echo "hfouvyAdpy/ofu" | perl -pe 's/(.)/chr(ord($1)-1)/ge' gentux's gpg fingerprint ==> 34CE 2E97 40C7 EF6E EC40 9795 2D81 924A 6996 0993 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (GNU/Linux) iD8DBQFDbwOjLYGSSmmWCZMRAmG9AJ46OE4xLI3pCKnb3RTQSCIGWNKSBgCfWOOl V9zFRF6QNqmVSK0LHjt4e9c= =tnMC -----END PGP SIGNATURE----- -- [email protected] mailing list
