A NOTE has been added to this issue. ====================================================================== https://austingroupbugs.net/view.php?id=1556 ====================================================================== Reported By: calestyo Assigned To: ====================================================================== Project: Issue 8 drafts Issue ID: 1556 Category: Shell and Utilities Type: Clarification Requested Severity: Objection Priority: normal Status: New Name: Christoph Anton Mitterer Organization: User Reference: Section: Utilities, sed / 9.3.5 RE Bracket Expression Page Number: - Line Number: - Final Accepted Text: ====================================================================== Date Submitted: 2022-01-18 01:07 UTC Last Modified: 2022-01-18 09:41 UTC ====================================================================== Summary: clarify meaning of \n used in a bracket expression in a sed context address or s-command ======================================================================
---------------------------------------------------------------------- (0005621) geoffclare (manager) - 2022-01-18 09:41 https://austingroupbugs.net/view.php?id=1556#c5621 ---------------------------------------------------------------------- I believe the text is already clear what is required here. When it says "The escape sequence '\n' shall match a <newline> embedded in the pattern space", this clearly only applies when the backslash is special (otherwise it isn't an "escape sequence"). So \n does not match newline when it appears within \\n for example. The general rule for BREs is that backslash loses its special meaning in a bracket expression, therefore [\n] matches backslash or 'n', it does not match newline. GNU sed has the required behaviour when POSIXLY_CORRECT is set in the environment:<pre>$ printf 'a\nb\n' | (POSIXLY_CORRECT=1 sed -n 'N;/a[\n]b/p') $ $ printf 'a\nb\n' | (unset POSIXLY_CORRECT; sed -n 'N;/a[\n]b/p') a b $ </pre> Issue History Date Modified Username Field Change ====================================================================== 2022-01-18 01:07 calestyo New Issue 2022-01-18 01:07 calestyo Name => Christoph Anton Mitterer 2022-01-18 01:07 calestyo Section => Utilities, sed / 9.3.5 RE Bracket Expression 2022-01-18 01:07 calestyo Page Number => - 2022-01-18 01:07 calestyo Line Number => - 2022-01-18 09:41 geoffclare Note Added: 0005621 ======================================================================
