How can I make HISTSIZE work?

[Rashid Ali]

I changed HISTSIZE to 50 but when I run the command "history", it only shows 15 lines, why?
When I run "wc -l /.sh_history", it shows 60, which is more than HISTSIZE, why?

[Bill Hassell · Accepted solution]

The HISTSIZE variable limits the number of command accessible to the shell. If set to 50, things like ESC / (search) wil be limited to the most recent 50 lines in the HISTFILE. The HISTFILE grows without bounds.

history is not a command but a predefined alias to: fc -l and the man page for sh-posix says that this defaults to -16 (the most recent 16 lines). If you specify a larger history value (ie, history -150) than $HISTSIZE, only the most recent $HISTSIZE lines will be displayed.

[linuxfan]

Hi Zhang,

The default HISTSIZE is 128, any particular reason you reduced it to 50.

Do a history -50, to list the last 50 commands in your history.

-HTH
Ramesh

[Rashid Ali]

But if ~/.sh_history file can grow without bounds, how come I never see this file become very big and I never need to trim this file?
Also, I can't trace the commands I keyed in two months ago using ESC, why?

[Rashid Ali]

But if ~/.sh_history file can grow without bounds, how come I never see this file become very big and I never need to trim this file?
Also, By using ESC I can't trace the commands I keyed in two months ago , why?