Tips on sed
Replace String
MyString=" ... "</code> by <code>MyString="NOTFOUND"
cat file.xml | sed 's/\(MyString=\)\(.*\)/\1"NOTFOUND"/'
Delete all but a range of lines found between two regexp
cat loop_tree.tex | sed '/regexp1/,/regexp2/!d'
Rename all files names "mystring_file..." to "file..."
for f in `ls *mystring*`; do mv $f `echo $f | sed 's/mystring_//'`; done
Replace inside a file”
sed -i 's/ugly/beautiful/g' myfile.txt