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Re: errors in sed manual 4.2.2


From: bamber ward
Subject: Re: errors in sed manual 4.2.2
Date: Sat, 9 Aug 2014 15:15:51 +0100

I have tried to construct examples to test out \`(backslash backtick) but
have not succeeded  in getting the responses  I want. I assume that
backtick is the same as backquote. Backticks as in `command`.
for instance,
echo cat | sed "s/\`cat/bingo/"
gives cat
echo cat | sed "s/\`cat\'/bingo" # double quotes because of single quote
gives cat
but
echo cat | sed "s/cat\'/=/" gives
=


On Sat, Aug 9, 2014 at 2:13 PM, bamber ward <address@hidden> wrote:

> Unfortunately,  errors in the documentation seem to persist. Somewhat
> disapointing but correcting
> bugs is, I find, a good way to really understand a language.
>
> Section 4.7
> add
> s/.*// after last h
> to see why just run the program as given in the manual.
>
> Sections  4.9  and 4.10
> in S!{
>   h
>   b
> }
> add s/.*// after h
> omit final p
> without these changes you get, for
> a file containing,
> the cat sat
> on the mat # no new line here
> baa
> 23
> 23
>
> instead of 23
>
> 4.15
> I see you have added the -n option   to this edition to try to correct
> this script.
> However, the comment in the script should state print the second(not
> first) duplicated line
> The program still does not  give the correct output
> cat uniq_d3.txt
> dog
> dog
> cat
> cat
> pony
> gives output:
> dog
> cat
> cat
> pony
>
> instead of :
> dog
> cat
>
> The script prints out the last line regardless and if the last two lines
> are different it prints both.
> Replacing the last $b by
> $ s/.*/ / seems to fix it
> Possibilities
> Last two lines different.Can't be duplicates so delete
> Last two lines duplicates.
> Last line added in the code block.
> Last but one line deleted
> Then Last line printed so ok to delete pattern space at end.
> 4.17
> Need to remove the first p in the last script to avoid duplicated output
>
> I hope you find this helpful
> Best Wishes
>
> David
>


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