bash' command history

[Sven-Erik Petermann]

Hi

Why isn't there a method in command history management that prevents 
adding the current command line to the history, if it's already there?
Say, I run a program ./a 20 times in a row, this causes the history to 
be filled with 20 lines of the string "./a". For me, it's pointless and 
very annoying.
So, I altered the add_history function in lib/readline/history.c and the 
result was:
add_history first checks if the string to be added is already in 
history, if it's not, it proceeds and adds the line to history. But, if 
the line is already in history then entries after the line found (that 
contains the command currently being added to the history) are moved 
down one slot and the current command line is moved to the top of the 
history.
So, is this kind of feature somehow insecure or unwanted, or are you 
interested in the lines of code I added?

Sven-Erik Petermann
University of Tartu