On Tue, 2007-03-13 at 22:04 +0200, Dotan Cohen wrote: > On 13/03/07, Marc Schwartz <marc_schwartz@xxxxxxxxxxx> wrote: > > Dan Track wrote: > > > Hi > > > > > > Could someone please tell me how I can grep for two or more different > > > words in one command instead of piping them through. > > > > > > e.g I don't want to do > > > > > > cat /tmp/file | grep -v cat | grep -v grey > > > > > > I'd like to run that from one grep command. > > > > > > Many Thanks > > > Dan > > > > Two possibilities: > > > > $ cat .Xresources > > Emacs.default.attributeBackground: white > > Emacs.default.attributeForeground: black > > ! > > XEmacs*EmacsFrame.default.attributeForeground: black > > XEmacs*EmacsFrame.default.attributeBackground: white > > ! > > xterm*geometry: 100x32 > > xterm*faceName: bitstream vera sans mono > > xterm*faceSize: 12 > > xterm*background: white > > xterm*rightScrollBar: true > > > > > > # Use grep with the -E arg to specify extended > > # regex usage > > > > $ cat .Xresources | grep -Ev "(white|black)" > > ! > > ! > > xterm*geometry: 100x32 > > xterm*faceName: bitstream vera sans mono > > xterm*faceSize: 12 > > xterm*rightScrollBar: true > > > > > > # Or just use egrep > > > > $ cat .Xresources | egrep -v "(white|black)" > > ! > > ! > > xterm*geometry: 100x32 > > xterm*faceName: bitstream vera sans mono > > xterm*faceSize: 12 > > xterm*rightScrollBar: true > > > > > > You might want to look at: > > > > http://en.wikipedia.org/wiki/Regular_expression > > http://www.regular-expressions.info/ > > > > There is also a great book: > > > > http://regex.info/ > > > > HTH, > > > > Marc Schwartz > > > > > >From Dan's question, it appears that he wants AND behaviour, not OR > behaviour, from the two greps. > > Dotan Cohen Dotan, Keep in mind that he is EXCLUDING lines that have those two values, so in this case, the use of '|' (OR) gets the desired result. A line cannot have either value, which is the same as saying that a line cannot have both values. If he wanted lines that INCLUDED both values, then the approach would require the piped double grep approach, considering more complicated lookahead or lookbehind references, using [g]awk or other alternatives. One approach, for example, might be to use a Perl based Regex, with Lookahead. This one will return lines in .Xresources that have BOTH 'xterm' AND 'white' in them: $ grep -P "(?=.*xterm)(?=.*white)" .Xresources xterm*background: white or return lines that have BOTH 'default' AND 'ground': $ grep -P "(?=.*default)(?=.*ground)" .Xresources Emacs.default.attributeBackground: white Emacs.default.attributeForeground: black XEmacs*EmacsFrame.default.attributeForeground: black XEmacs*EmacsFrame.default.attributeBackground: white In this way, we can combine multiple regex's in a single grep call. HTH, Marc
