I have a file that is made up of two vertical parts. On the left side, the data is already formatted and I don't want to change it. I only want to format the data on the right side. Say I have a file with lines likefoo=bar baz     # Neato       Junkquux=xyzzy      # Bilbo Baggins Ringwith many more lines like that. I only want to modify the text to the right of the '#' character. I selected the text I want with the following expressions:gg/#ctrl-vG$but if I then try to modify it (say, with :'<,'>!column -t), it actually modifies the entirety of every line. What is the correct expression to use to only modify the visually selected parts?
How to modify visually selected block with external command?
visual mode;external command
You can also try:gg^VGt#d:%!column -tggPFrom :h :visual_example:Currently the : command works on whole lines only.  When you select part of a line, doing something like :!date will replace the whole line.  If you want only part of the line to be replaced you will have to make a mapping for it.  In a future release : may work on partial lines.See also :h visual-operators for details.