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Ah! So, is
~/.history written only at exit time or log out time?
I just realised, the last update to the file was more than six hours ago:
Code:
% ls -hl .history
-rw------- 1 grahamperrin grahamperrin 29K 10 Jul 20:48 .history
% date
Sun 11 Jul 2021 02:40:54 BST
%
I think so but didn't actually check. I did notice that it remembered the commands I had entered during that login session before I created the file.
As the non-root user, first I entered the
chsh command, and, as expected, nothing had changed: I still had the $ prompt,
echo $SHELL still output /bin/sh, and I was still using the /bin/sh commands (for example,
x=x did not produce a syntax error). So I then logged out and back in. Lo and behold, I had the /bin/csh shell and the % prompt, but no
.history file, so I created it, logged out and back in again -- call this login session number 3. The history file had all the commands from login session number 2, but contained no commands from login session number 1.
This was all more or less as expected. Using the sh shell, it always remembers all the commands from the present login session, but none from previous login sessions. What I infer from that is that the sh shell keeps all the present session's commands in memory, but then loses that memory when you log out, whereas the csh shell writes them in the
~/.history file.
The /bin/bash shells I use in Linuxland also keep history, but in
~/.bash_history files. I don't use any other shells. I used to use ksh on AIX systems, but that was many years ago, and I could be mistaken, but I don't remember any of those old unixes keeping any history at all, even for the current login sessions. SCO used /bin/sh IIRR. I don't remember what shell the DEC systems used.
Looking at my /bin/bash and /bin/csh history files right now, the last commands in those files is consistently
exit in four of those files. Just guessing-- maybe you are shutting down your system without logging out some times?
