method
save_history=
save_history=(val)
public
Sets IRB.conf[:SAVE_HISTORY] to the given val and calls #init_save_history with this context.
Will store the number of val entries of history in the #history_file
Add the following to your .irbrc to change the number of history entries stored to 1000:
IRB.conf[:SAVE_HISTORY] = 1000