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What are core files and how can I delete them when am performing system maintenance??


 
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# 1  
Old 04-03-2002
What are core files and how can I delete them when am performing system maintenance??

Help me

How can I go about doing this.
also, if you have any idea of other files I can delete and what I can do to improve the performance of a system thats running too slow
# 2  
Old 04-03-2002
homework?

After looking at you other posts, it is clear that you are inexperienced with unix and it appears that this may be homework, but it is a simple question so I will answer.

Use the find command, do a "man find" and it will show you quite a bit about how to format the command. There are some examples at the bottom of the listing.

Also, you can go to a good UNIX tutorial website or go to www.itrc.hp.com and use the search option to browse the MAN pages. Although this is for HPUX, the find command is generic for the most part.

Have fun learning UNIX!





Smilie
# 3  
Old 04-03-2002
Definitely homework - I've seen this exact question before!

A tip - this site isn't for homework questions - and you won't get too much help if people suspect that's the nature of your post.

However - where this site is useful is the searching functions. There's a wealth of previously asked questions and associated discussions (even on this specific topic) - which will most likely answer your questions.

Theres nothing wrong with coming here to bounce ideas of ask specific questions releated to stuff you are learing. But you'll have to make an effort to understand if first - then you'll find you will get a much warmer response.

Friendly advice for all those that do sumit their homework questions here! Smilie
# 4  
Old 04-03-2002
Just for the record, I am that same guy called IMPORTANT

now, I never post no homework questions because I am learning unix myself. I am not going to school or whatever it is most of you did to know unix.

I dont and will never understand why people just cant give answers. If you dont know it or you dont want to reply, it will be highly appreciated if you dont reply at all.

me, when I see someone ask a question I know the answer to, there's nothing stopping me from answering the questions regardless.

There's nothing better than an answer from someone experienced in unix who knows what and what not to do with specific commands. and no, the man pages is definitely NOT a good place to refer anybody to. the man pages should only be used for definitions of command.

I learn from seeing examples given by experts or should I say experienced administrators. the man pages can never, and I mean NEVER compare to examples given by a unix administrator. They know what to do. they do it on a constant basis. and I will be really suprised if someone has the nerve to actually disagree that man pages are the best place to learn commands

this may sound disrespectful to most if not all you reading this, but this is the truth you need to take notice of.

and by the way, a true thanks to all of you who have actually helped me and answered my past questions. I really appreciate your help
# 5  
Old 04-04-2002
I totally agree with TRUEST. Lot of guys here are learning UNIX. If people think that the question is 'homework' , then PLEASE DO NOT REPLY to the question. And, how can you come to a conclusion that it is a HOMEWORK question?

Smilie
# 6  
Old 04-04-2002
Things that are homework are usually easy to spot....they typically don't have any real life application. Often the same questions are asked repeatedly - in almost the same wording by different users.

There has been much discussion in the forum about 'homework" and I beleive that the rules state that there are to be no homework questions asked.

That is not to say that if you have made a decent attempt at the answer - then it is'nt appropriate - that is the ideal time to use the forum. It's just when people blatently ask questions without any effort at a discovery being apparent - that people will not be likely to help.

I'd also wager that most users in this forum didn't learn unix at school or college at all. I'd suggest most are self taugh - or from a book (like me).

Smilie
# 7  
Old 04-04-2002
I am self taught in Unix as well (as is painfully obvious in some of my assumptions past (and future)). However, I know for a fact in my experience that trying to learn every possible solution to every problem is not possible. You have to understand the system first, then create or figure out your own solutions. Yes, people get stumped sometimes. It's OK to ask for help. But no one will hold your hand for everything.

And if I do honestly think a question is obvious homework (and usually other believe the same) I do not hesitate to close the thread right away. This question may not be homework, but it's such a pointed and narrow question for such a broad subject that many people may take it to be homework.

Anyways, here's a website on old core memory, before the nifty little DIMMs / SIMMs used more recently:
http://www.psych.usyd.edu.au/pdp-11/core.html
Most systems now use moderm memory, but you'll still hear terms that are a throwback to this memory, like "core dump" or "in-core image".
A core file, or core dump, is basically an abnormally aborting process dumping all of it's physical memory to disk. It's useful for debugging. They are typically files called "core". If you use the command "file core", many systems will tell you what process created the file.

Getting rid of unnecessary core files is like taking out the trash at home - if it was never done, your kitchen would eventually fill up.
It may not slow your system down very much, like rotting fruit on your kitchen counter doesn't affect how long you have to bake your cookies, but then again, who wants rotting fruit on their counter?

There lots of maintenance you can be doing - cleaning up core files is one of them. There's also hardware maintenance, software upgrades, etc...

As for finding core files, run as root:
"find / -type f -name core > /tmp/core-list 2>/dev/null"
Next, examine each file to make sure it's not needed by a developer or system engineer, and delete the ones that are just taking up space.

And as for not liking the man pages, after a while, you'll probably start hearing a lot of people telling you to RTFM (Read The F***ing Manual). Man pages are a wonderful resource, and no Unix admin or guru can do without them. Learn how to effectively search the man pages (man -k keyword), and search google for answers, since many people have probably had similar questions in the past. Some systems also use the "info" program, which is like a newfangled man page system. It's a little more interactive, and almost navigatable like html, but frankly, I'll take a man page any day.
 

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