tcl : compare 2 file with diff and grep the output

Question

I would like to compare 2 file and show the difference between files

when I use the following :

exec sh -c "diff -w file1 file2 \|grep \<"

but no result is shown and the script is brokeen

what's wrong with the tcl command ?

Answer 1

The following will work:

puts [exec sh -c "diff -w file1 file2 |grep \\<"]

The < needs to be double-backslashed, and the output should be printed.