Sed Command – Replace First Matching Character

regular expressionsedtext processing

Trying to update some latex code. The four lines:

something $^\text{TT}$ and more stuff
something $^\text{T}$ and more stuff
something $^\text{M\times N}$ and more stuff
something $^\text{T} {otherstuff}$

should turn into

something $^{\text{TT}}$ and more stuff
something $^{\text{T}}$ and more stuff
something $^{\text{M\times N}}$ and more stuff
something $^{\text{T}} {otherstuff}$

In other words, encase the super-script by an extra {...}.

My attempt at using sed is the following

sed 's/\^\\text{\(.*\)}/\^{\\{text{\1}}/' testregex

This works on the first three lines, but the final line doesn't work and produces

something $^{\text{T} {otherstuff}}$

instead. The problem is that sed is matching with the last } on each line, but I need it to match the first } after the \text{

Also, it would be great if this could work multiple times on the same line, for example,

^\text{1} la la la ^\text{2}

should turn into

^{\text{1}} la la la ^{\text{2}}

I'm sure there's just one tiny little modification to make it work, but I can't figure it out and it's driving me nuts. Thanks in advance!

Best Answer

One method to overcome the greedy regular expression problem is to explicitly look for a string of non-delimiter characters, followed by the delimiter character. At the same time, you can probably simplify your replacement syntax via:

sed 's/\^\(\\text{[^}]*}\)/\^{\1}/' input.tex

It should be possible to use

sed 's/\^\(\\text{[^}]*}\)/\^{\1}/g' input.tex

for multiple matches per line.

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