Emacs takes unbelievably long to start without a fully qualified domain name (FQDN).
I would like to know what elisp commands in the .emacs file could speed it up without a FQDN e.g. using a fake system-name.
You can't solve this issue in ~/emacs since the wait takes place before this file is even loaded.
Related
I can use process-name to get the name of the process, but can I change the name after starting it? I looked in the manual, and even in the source and haven't found anything that seems like it would do this.
There's only one line in Emacs' process.c source file where p->name is set for a process p, and that is in the function make_process. All other functions just read that value, they never (re-)set it. So it seems the answer to your question is "no".
You could, of course, try to implement your own function that changes the name of a process. See here
for more information.
Maybe I'm wrong, but I am convinced there is some facility provided by UNIX and by the C standard library to get the OS to delete a file once a process exits. But I can't remember what it's called (or maybe I imagined it). In my particular case I would like to access this functionality from perl.
Java has the deleteOnExit function but I understand the deletion is done by the JVM as opposed to the OS which means that if the JVM exits uncleanly (e.g. power failure) then the file will never get deleted.
But I understand the facility I am looking for (if it exists), as it is provided by the OS, the OS looks after the file's deletion, presumably doing some cleanup work on OS start in the case of power failure etc., and certainly doing cleanup in the case the process exits uncleanly.
A very very simple solution to this (that only works on *nix systems) is to:
Create and open the file (keep the file handle around)
Immediately call unlink on the file
Proceed as normal using the file handle, and exit when you feel like it
Then when your program is complete, the file descriptor is closed and the file is truly deleted. This will even work if the program crashes.
Of course this only works within the context of a single script (i.e. other scripts won't be able to directly manipulate the file, although you COULD pass them the file descriptor).
If you are looking for something that the OS may automatically take care of on restart after power failure, an END block isn't enough, you need to create the file where the OS is expecting a temporary file. And once you are doing that, you should just use one of the File::Temp routines (which even offer the option of opening and immediately unlinking the file for you, if you want).
You're looking for atexit(). In Perl this is usually done with END blocks. Java and Perl provide their own because they want to be portable to systems that don't follow the relevant standards (in this case C90).
That said, on Unix the common convention is to open a file and then unlink it; the kernel will delete it when the last reference (which is to say, your file descriptor) is closed. You almost always want to open for read+write.
I think you are looking for a function called tmpfile() which creates file when called and deletes it upon close. check, article
You could do your work in an END block.
I am attempting to edit a remote file in Emacs, and I'm having trouble getting from the documentation and previous SO questions to doing the thing I want.
I'm working remotely, from a variety of locations, and I want to edit files on server Foo. Server Foo isn't directly reachable from the Internet, but server Bar is, and Foo accepts connections from Bar. I can count on reaching Bar, and Bar can count on reaching Foo.
The Tramp documentation tells me that I need to add to Tramp's proxy list to do this, and that it should look like the following:
(add-to-list 'tramp-default-proxies-alist
("foo_host" "seanm" "/ssh:seanm#bar_host"))
However, when I try that, it doesn't work, and I get inscrutable error messages.
How can I unambiguously refer to Foo? There is no DNS server that knows how to find Foo from its hostname, and Foo's IP address is in the 10.0.0.0/8 private space. I don't want to refer to Foo by that IP address, because that risks colliding with hosts in other 10.0.0.0/8 networks I may visit. As a kludge, I added Foo to Bar's /etc/hosts file, but that didn't seem to work. Is there a better solution?
What quoting rules do I need to adhere to? The examples that I'm seeing use both "double quotes" and `tick-and-single' quotes, the latter apparently requiring double-backslash escaping. I don't understand what's going on there - it seems like there are multiple layers of parsing that this string is going to be shoved through.
While trying variations on this, I've gotten error messages that amount to "you can't use that remote-access method for that scenario." How can I set up a second proxy method that will let me do the equivalent of C-x C-f /su::/path/to/file ?
It all seems very painful compared to the previous multi-hop syntax.
Later: I was able to get the many layers of escaping right so that emacs correctly 'hears' the names of hosts. However, I can't get any hops beyond a second to work correctly, which is a very disappointing lapse in functionality.
The correct answer turned out to be modifying my SSH config with Host, HostAlias, and ProxyCommand directives.
SOLVED see Edit 2
Hello,
I've been writing a Perl program to handle automatic upgrading of local (proprietary) programs (for the company I work for).
Basically, it runs via cron, and unfortunately has a memory leak (or something similar). The problem is that the leak only happens when I'm not looking (aka when run via cron, not via command line).
My code does not contain any circular (or other) references, so the commonly cited tools will not help me (Devel::Cycle, Devel::Peek).
How would I go about figuring out what is using so much memory that the kernel kills it?
Basically, the code SFTPs into a server (using ```sftp...`` `), calls OpenSSL to verify the file, and then SFTPs more if more files are needed, and installs them (untars them).
I have seen delays (~15 sec) before the first SFTP session, but it has never used so much memory as to be killed (in my presence).
If I can't sort this out, I'll need to re-write in a different language, and that will take precious time.
Edit: The following message is printed out by the kernel which led me to believe it was a memory leak:
[100023.123] Out of memory: kill process 9568 (update.pl) score 325406 or a child
[100023.123] Killed Process 9568 (update.pl)
I don't believe it is an issue with cron because of the stalling (for ~15 sec, sometimes) when running it via the command-line. Also, there are no environmental variables used (at least by what I've written, maybe underlying things do?)
Edit 2: I found the issue myself, with help from the below comment by mobrule (in response to this question). It turns out that the script was called from a crontab of a user (non-root) just once a day and that (non-root privs) caused a special infinite loop situation.
Sorry guys, I feel kinda stupid for not finding this before, but thanks.
mobrule, if you submit your comment as an answer, I will accept it as it lead to me finding the problem.
End Edits
Thanks,
Brian
P.S. I may be able to post small snippets of code, but not the whole thing due to company policy.
You could try using Devel::Size to profile some of your objects. e.g. in the main:: scope (the .pl file itself), do something like this:
use Devel::Size qw(total_size);
foreach my $varname (qw(varname1 varname2 ))
{
print "size used for variable $varname: " . total_size($$varname) . "\n";
}
Compare the actual size used to what you think is a reasonable value for each object. Something suspicious might pop out immediately (e.g. a cache that is massively bloated beyond anything that sounds reasonable).
Other things to try:
Eliminate bits of functionality one at a time to see if suddenly things get a lot better; I'd start with the use of any external libraries
Is the bad behaviour localized to just one particular machine, or one particular operating system? Move the program to other systems to see how its behaviour changes.
(In a separate installation) try upgrading to the latest Perl (5.10.1), and also upgrade all your CPAN modules
How do you know that it's a memory leak? I can think of many other reasons why the OS would kill a program.
The first question I would ask is "Does this program always work correctly from the command line?". If the answer is "No" then I'd fix these issues first.
On the other hand if the answer is "Yes", I would investigate all the differences between having the program executed under cron and from the command line to find out why it is misbehaving.
If it is run by cron, that shouldn't it die after iteration? If that is the case, hard for me to see how a memory leak would be a big deal...
Are you sure it is the script itself, and not the child processes that are using the memory? Perhaps it ends up creating a real lot of ssh sessions , instead of doing a bunch of stuff in one session?
Every time I initiate company-mode with M-x company-mode this message shows up:
Company back-end 'company-semantic' could not be initialized
Company back-end 'company-ropemacs' could not be initialized
Company back-end 'company-pysmell' could not be initialized
The completion works but I wonder whats the meaning of that message and how to fix it.
EDIT: I moved company-semantic.el company-ropemacs.el company-pysmell.el to ~.emacs.d\plugins\company-0.4.3\unused-backends but I'm still getting that error.
Instead of changing your company-mode install directory. Just define company-backends in your .emacs file. E.g.
(setq company-backends '(company-elisp
company-ropemacs
company-gtags
company-dabbrev-code
company-keywords
company-files
company-dabbrev))
Excluding the backends you do not want to support from the list.
semantic, ropemacs and pysmell are all emacs extensions. Do you have them installed?
If you don't intend to use them, a quick workaround would be to remove or move that files that define those back-ends, which would prevent company mode from trying to load them.
cd /location/of/company
mkdir unused-backends
mv company-semantic.* company-ropemacs.* company-pysmell.* unused-backends/
As long as you do not add unused-backends to your load-path, this will fix the problem.
If you want to use those backends (semantic is a parser for better context-appropriate emacs actions based on language, pysmell and ropemacs are both for usage with python), then installing them should fix this problem.