problems with 2 system functions

[ednorton]

About every 3rd or 4th time I log in and try to look at the history of my commands from the previous session they aren't there. The history list only includes commands from sessions before the previous session. Any ideas what happens to my command history from these "ghost" sessions?

Also, on my system the grep -f option doesn't work properly. Normally when using the -f option with grep one specifies a file in which a list of things to check for match for is listed. But when I use this option the system takes some time to run (depending on how long the list of things to check for is and how big the file to be checked is) and returns all the items in the original file as though nothing even was checked for. No matter what the list is the same origianl file is returned. For example if I have a file which includes a b c d e and then specify via the -f option and a match file that I want to check for an a and a c the command returns a b c d e. If i change the match file to include an e I still get returned a b c d e and so on. If i use the same exact commands and files on another system I get correct results. If the -f option were disabled I would thin I'd get some kind of eror message. Any ideas? Given that this doesn't work properly and gives no error messages or warnings I'm alittle concerned about other commands and command options.

[Roxoff]

It could be something quite mundane, but missing command history and unusual behaviour from system tools suggests you might have been compromised.

Take a look at what's running (pstree and top) and check what network connections are live (netstat).

If you suspect this might have happened disconnect your network connection, boot up with a live CD if you can and examine the logs from a safe environment.