One-liner to fix LaTeX quotation marks

tim_the_monk has asked for the wisdom of the Perl Monks concerning the following question:

Hello monks,

I would like to replace all double quotation marks (") in a text document which are not directly followed by the a ´tick (') or a backtick (`) with ticks.

For example, the text

This is "an example", but "`this not"'.

Should look like this afterwards:

This is 'an example', but "`this not"'.

The background is LaTeX: I have a german document that contains proper german quotation marks (the 'this not' part above) as well as broken ones (the 'an example' part).

Does anybody know a Perl one-liner on the command line for this?

Thanks in advance,

Tim

I tried

cat file.txt | perl -pe 's/\"[^[\'\`]/"`/g'
[download]

but something is wrong, the shell wants more input.

Comment on One-liner to fix LaTeX quotation marks Select or Download Code

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Re: One-liner to fix LaTeX quotation marks by LanX (Saint) on Oct 14, 2012 at 19:40 UTC
what you are looking for is called "negative look ahead" see http://perldoc.perl.org/perlretut.html#Looking-ahead-and-looking-behind DB<100> $txt=q( This is "an example", but "`this not"'. ) => " This is \"an example\", but \"`this not\"'. " DB<101> $txt =~ s/"(?![`'])/'/g => 2 DB<102> $txt => " This is 'an example', but \"`this not\"'. " [download] but you might get bitten by shell escaping if you try a one-liner Cheers Rolf	[reply] [d/l]
Re^2: One-liner to fix LaTeX quotation marks by tim_the_monk (Initiate) on Oct 14, 2012 at 19:56 UTC
Thanks a lot for the info and link.	[reply]
Re: One-liner to fix LaTeX quotation marks by aitap (Curate) on Oct 14, 2012 at 19:48 UTC
cat file.txt \| perl -pe 's/\"[^[\'\`]/"`/g' [download] but something is wrong, the shell wants more input. This is because you can't really escape anything in single quotes in UNIX shell. You have to write the command like this: $ perl -pe "s/\"([^'\`])/'\$1/g" This is "an example", but "`this not"'. This is 'an example', but "`this not"'. [download] Sorry if my advice was wrong.	[reply] [d/l] [select]
Re: One-liner to fix LaTeX quotation marks by hippo (Archbishop) on Oct 14, 2012 at 22:59 UTC
While others have answered your specific question, I shall instead point out that you will almost never want to do this: `cat file \| command` as it is a waste of a process (the cat) which gains nothing. Instead you can do this: `command < file` thus avoiding what used to be called the UUoCA. Nothing to do with perl, but a valuable concept nonetheless.	[reply] [d/l] [select]
Re: One-liner to fix LaTeX quotation marks by CountZero (Bishop) on Oct 15, 2012 at 07:50 UTC
Perhaps not directly applicable to your post, but nevertheless very useful if you use LaTeX a lot and have to transform non-LaTeX to properly formatted LaTeX: LaTeX::Encode. It has an "intelligent quotes - iquotes" option in its main `latex_encode` routine. single or double quotes around words will be changed to LaTeX single or double quotes; double quotes around a phrase will be converted to "``" and "''" and single quotes to "`" and "'". This is sometimes called "intelligent quotes" So once you have replaced your double quotes by single quotes where necessary, you can run your text through `latex_encode` to get proper opening and closing quotes. CountZero A program should be light and agile, its subroutines connected like a string of pearls. The spirit and intent of the program should be retained throughout. There should be neither too little or too much, neither needless loops nor useless variables, neither lack of structure nor overwhelming rigidity." - The Tao of Programming, 4.1 - Geoffrey James My blog: Imperial Deltronics	[reply] [d/l] [select]
Re: One-liner to fix LaTeX quotation marks by grizzley (Chaplain) on Oct 15, 2012 at 07:19 UTC
If you want to override existing file you can use `-i` option: `perl -i -pe 'your script' file.txt`	[reply] [d/l] [select]