[Tex/LaTex] search and replace string in all files

editors

I realize that this might not strictly be a LaTeX question but I have still decided to post the question here as other's might have the same problem on occasion.

I am working on a rather large document at the moment that contains a bunch of equations. Instead of writing them as:

    Q^{h}_{Con} = 0.15 \cdot Q^{h}_{Transm} + ...

I would rather do this:

\newcommand{\qCon}{Q^{h}_{Con}}
\newcommand{\qTransm}{Q^{h}_{Transm}}
...
\qCon = 0.15 \cdot \qTransm + ...

Now it is not hard to do this if you have that idea when you start writing on a document. In my case however I already have many pages written (including a nomenclature). Now I would like to replace all mentions of e.g. $Q^{h}_{Con}$ with $\qCon$ . Doing this I could make sure that I don't have a typo somewhere and up with a $Q^{h}_{Com}$ .

Going through all files on their own is way too complicated and the tex editor I am using only offers search and replace in all opened files. So I have tried to use the Terminal (on Mac) to do so. I have been able to use 'grep' to find all the instances of e.g. $Q^{h}_{Con}$ but could not figure out how to replace it with $\qCon$ .

Anyone has an idea?

Best Answer

something like

for i in *.tex
do
sed -i -e 's/Q^{h}_{\([a-zA-Z]*\)}/\\q\1 /g' $i
done

Probably does something. (Save a copy of your files first:-)

Option 1: `sed`

The stream editing tool, sed, would be a natural first choice, but the problem is that sed can't match non-greedy regular expressions.

We need a non-greedy regular expression here- to clarify why, let's consider

sed -r 's/|(.*)|/\\abs{\1}/g' myfile.tex

If we apply this substitution to a file that contains something like

$|a|+|b|\geq|a+b|$

then we'll get

$\abs{a|+|b|\geq|a+b}$

which is clearly not what we want- regular expression matches like this are greedy by default.

To make it non-greedy, we typically use .*?, but the problem is that sed does not support this type of match. Happily (thanks Hendrik) we can use the following instead

sed -r 's/\|([^|]*)\|/\\abs{\1}/g' myfile.tex

Once you're comfortable that it does what you want, you can use

sed -ri.bak 's/\|([^|]*)\|/\\abs{\1}/g' myfile.tex

which will overwrite each file, and make a back up first, myfile.tex.bak

Option 2: `perl`

We could, instead, use a little perl one-liner:

perl -pe 's/\|(.*?)\|/\\abs{\1}/g' myfile.tex

When you're sure that you trust it is working correctly, you can use the following to overwrite myfile.tex

perl -pi -e 's/\|(.*?)\|/\\abs{\1}/g' myfile.tex

You can replace myfile.tex with, for example, *.tex to operate on all the .tex files in the current working directory.

Details of perl's switches are discussed here (for example): http://perldoc.perl.org/perlrun.html#Command-Switches

Best Answer

Related Solutions

[Tex/LaTex] Latex editor for Linux that allows multiple instances

[Tex/LaTex] Automatically replace all |foo| with \abs{foo}

Option 1: sed

Option 2: perl

Related Question

Option 1: `sed`

Option 2: `perl`