Introduction to sed

Post by dramaticus3 » Sat, Oct 08, 2011, 11:25 AM UTC

dbbo wrote: post #19

_delirium wrote: post #17

Earlier quoted context omitted.

On the speed question, I actually find Perl considerably faster than sed in a lot of use-cases, if there's enough processing to dominate the slightly higher startup costs of Perl. For example, at one point I had reason to take a gigantic single-line textfile, and break it into lines based on a specific 3-letter pattern that didn't occur anywhere else: s/ABC/A\nC/g In whatever sed comes with Debian, this took about 10…

The copyright section of sed(1) suggests that the Debian package sed (I'm running wheezy) is Gnu sed 4.2.1[1]. Plan9 sed is also available in the 9base package. I'm running perl 5.12.4 (also from Debian testing). I don't see any significant difference in speed with vanilla 5.14.1 and the commands I mentioned earlier. [1] http://www.gnu.org/software/sed/

Post by freemarketteddy » Sun, Oct 09, 2011, 6:48 AM UTC

grok2 wrote: post #15

freemarketteddy wrote: post #8

I dont know if this off topic but is there an utlity that can parse C files and print all the function names or local variable names for example. I know it can be done through sed,but a perfect regex for parsing functions and nothing else can be complex and I am wondering if someone has already done it.

Look at what the perl script at http://www.gson.org/egypt/ does -- if you are using gcc, you can compile with certain options to generate info from the source code into an intermediate file and then parse this intermediate file with a script to get the info you need. A bit complex, but useful if you are trying to read through code you are maintaining. A compiler is better than a regex for this, I think, for C. Also c…