Shell

• bash
• zsh
• ksh

diff -u file1 file2 \
| wdiff -d \
        --start-delete "`tput setaf 1``tput bold`" \
        --start-insert "`tput setaf 2``tput bold`" \
        --end-delete   "`tput op``tput sgr0`"      \
        --end-insert   "`tput op``tput sgr0`"      \
        | less -S -R

Credits:

• https://homepages.inf.ed.ac.uk/imurray2/compnotes/cwdiff/cwdiff

I don't have any knowledge about them, but there are C-Shells

• csh (Link to Wikipedia : C-Shell)
• tcsh (Link to Wikipedia : tcsh)