Substitua o texto por sed
sed -i 's/old-text/new-text/g' input.txt
Clear Caterpillar
sed -i 's/old-text/new-text/g' input.txt
#on my mac
sed -i -e 's/old-text/new-text/g' text.txt
You can try this sed command
sed 's/,\(.*china\)/,Tomas_proxy.lt\/\1/' FileName
or
sed 's/,\(.*china\)/,Tomas_proxy.lt\/\1/' FileName > NewFile
or
sed -i.bak 's/,\(.*china\)/,Tomas_proxy.lt\/\1/' FileName