I am pretty new to vim and ex and I was wondering if anyone could help me with an area I am fuzzy on. I would like to know how to swap characters on every line or occurrence of a pattern. For example How would I swap the first 2 characters of every line in a file. I know it can be done and I'm pretty sure it involves the use of parentheses to store the chars. But thats is all I know. Also, Say I wanted to replace the 2nd char on everyline with some string, how would I do that?
To replace second character in each line to r in vim: :%s/^\(.\)./\1r/:
:%s/p/r/ replace pattern p with r for all lines (because of %);^ start line;\( start a group;. any character (the first in this example);\) end the group;. any character (the second in this example);\1 back reference to the first group (the first character in this example);r replacement text.To swap two first characters: :%s/^\(.\)\(.\)/\2\1/.