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Robert Buchholz wrote: |
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> On Tuesday, 25. September 2007, Donnie Berkholz wrote: |
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>> On 20:04 Mon 24 Sep , Doug Goldstein (cardoe) wrote: |
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>> > if ! use usb; then |
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>> > sed -i util/Makefile \ |
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>> > -e '/ttusb_dec_reset/d' \ |
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>> > -e '/dib3000-watch/d' |
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>> > fi |
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>> > |
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>> > # do not compile test-progs |
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>> > sed -i Makefile -e '/-C test/d' |
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>> |
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>> You might want to die if these seds fail. |
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> |
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> I already wondered a while back: |
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> sed only fails if the file does not exist, but not if there was no |
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> replacement. Is there any way to force it to? |
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> |
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ed will exit with an error if a regex doesn't match: |
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ed -s util/Makefile <<< 'H |
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/ttusb_dec_reset/d |
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/dib3000-watch/d |
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w |
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q' || die 'ohNoes!' |
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I prefer to mute errors in an ebuild (after testing): |
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ed -s Makefile 2>/dev/null <<< $'/-C test/d\nw\nq' \ |
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|| die 'No match in Makefile' |
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..which I think is a lot easier to grok than the sed convolutions. |
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If it's supposed to be deleting every line with that regex (as the sed |
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currently does) I'd use: $'g/-C test/d\nw\nq' |
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I appreciate that ed seems hard (man ed is frightening!) but once you get |
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used to here-strings (and $' expansion) it's a doddle. (Use ,p instead of w |
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to see the output during testing.) |
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Tutorial: http://bash-hackers.org/wiki/doku.php?id=howto:edit-ed |
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Easier man page: http://plan9.bell-labs.com/magic/man2html/1/ed |
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Reference: http://www.opengroup.org/onlinepubs/009695399/utilities/ed.html |
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(I very much recommend that opengroup site as it outlines what a scripwriter |
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or programmer can expect on any POSIX/SuS compliant system.) |
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-- |
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