Talk:Sed

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Is there a reference for the claim of the last sentence?

Sed's language does not have variables and only primitive GOTO and branching functionality; nevertheless, the language is Turing complete. --HJH

Lots of Google references to "sed turing complete" say so, and it is not unreasonable to think that it would be. Use the file as a tape, and a special reserved symbol inserted into the file to mark the head position, use replace expressions to implement the transformation rules, and GOTOs to change state.


Or just encode the state using a set of several different 'head' symbols.

Here's an example of a UTM in sed:

See this sed script (http://sed.sourceforge.net/grabbag/scripts/turing.sed) with the accompanying explanation (http://sed.sourceforge.net/grabbag/scripts/turing.txt) -- EricP 04:24, 30 November 2005 (UTC)

I remove the "excellent" sed cheat sheet, which is constituted of copy pasted material from www.grymoire.com and the gnu manual. The author puts his copyright on this material, and fails to give credits ( and probably forgot to ask the permission from the author of the grymoire articles) even though he has been informed of this problems. —Preceding unsigned comment added by 146.124.141.250 (talk)


excellent cheat sheet is back, still no word of a permission to reproduce the content of www.grymoire.com, still no ack of copyright from the gnu sed man page. Users is spamming wikipedia with links to his websites —Preceding unsigned comment added by 146.124.141.250 (talk) 08:58, 15 November 2007 (UTC)

Why is this the primary page for SED? Shouldn't the reader be redirected to the disambiguation page? Is this acronym that much more significant than the other posible uses of the initials? —Preceding unsigned comment added by 71.249.130.166 (talk) 08:51, 4 October 2007 (UTC)

The disambiguation page can be found at the top of this page. IMO this is by far the most common usage of the word. --Kompik 15:39, 4 October 2007 (UTC)


[edit] Sed not faster than Awk

Sed is not faster than AWK. Sed's "regular" expressions aren't regular (see Regular_expression, since it allows back-references. As a result, strings can not necessarily be matched in sub-exponential time.

Also, in my personal experience, gawk is faster than GNU sed for simple grep-like tasks.

Serviscope Minor 00:55, 4 December 2007 (UTC)

[edit] move history above usage, history source?

why history is in between usage and examples? i'm not sure how it can be done here, thus let this proposition here.

http://www.engin.umd.umich.edu/CIS/course.des/cis400/sed/sed.html

tells another, i.e. year 1977, timeframe about `sed` developement