Editing an .ini file using regex or some form of pattern matching

Question

I have a file texstudio.ini, inside that file there is the following line

Tools\Commands\pdflatex=\"/usr/texbin/pdflatex" -synctex=1 -interaction=nonstopmode %.tex

I would like to change the above to

Tools\Commands\pdflatex=\"/bin/texliveonfly\" %.tex

without having to have to go inside the file and do it manually. In other words how could I do this using a bash script?

The file also contains several other command, for example

Tools\Commands\latexmk=
Tools\Commands\lualatex="lualatex -synctex=1 -interaction=nonstopmode %.tex"
Tools\Commands\makeglossaries=
Tools\Commands\makeindex=makeindex %.idx
Tools\Commands\metapost="mpost -interaction=nonstopmode ?me)"
Tools\Commands\pdf-chain=txs:///pdflatex | txs:///view-pdf
Tools\Commands\pdflatex=\"/bin/texliveonfly\" %.tex
Tools\Commands\pre-compile=
Tools\Commands\ps-chain=txs:///latex | txs:///dvips | txs:///view-ps
Tools\Commands\ps2pdf=ps2pdf %.ps
Tools\Commands\quick=txs:///compile | txs:///view
Tools\Commands\recompile-bibliography=txs:///compile | txs:///bibliography | txs:///compile

Answer 1

sed -i 's:pdflatex -synctex=1 -interaction=nonstopmode %.tex:Tools\Commands\pdflatex=\"/bin/texliveonfly\" %.tex:' test.ini