More 2¢ Tips!
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More 2¢ Tips!
Spinning Down Unused HDs
Date: Sat, 8 Nov 1997 18:34:07 +0100 (MET)
From: Philipp Braunbeck [email protected]
I guess there's no more need to emphasize how much we all like LG. Here's just my humble-newbie-one-and-a-half.
If You're like me and You've been upgrading for a couple of years now You're likely to have several HD's on Your IDE- or SCSI-Interfaces. Now there's probably some GNU-Linux-partition and one or more other partitions with M$-stuff on a separate disk. I've got a 120MB Conner (with actually nothing on it, I use it as a backup-device; it used to be win3.1, but I don't need it anymore :-) which is horribly loud. In the old days of DOS one friend of mine wrote a little Pascal-program which would stop the disk after a period of time, and it would only restart on some (hardware?)-interrupt. Some modern BIOSes can do that job for You, but people told me, that either it doesn't work on Linux (because the BIOS is only used on bootup in order to get some basic configuration) or it is not recommended to do so anyway.
When I was on some adventure-trip through /usr/sbin, I discovered some new species called "hdparm", which should be included on any major distribution. The manual page says that you can use it to spin down any drive on Your system! All You need to do now is putting a line like "hdparm -S1 /dev/hdb" in some boot-startup-script (I guess the filenames differ in different distributions) and You're done. What a silence!
However, You shouldn't do it with Your working /-partition, as it syncs the disk every now and then and the disk will keep starting and stopping, and this is definitely not good for any HD.
If You like my 2-cent just go ahead and publish it. If not, there will certainly be a good reason for this. As I am a newbie, i.e. I've been using GNU/Linux for about one year now, I'm humble enough to admit that this hint seems more than obvious to any experienced user. But if You decide to publish it, I'd prefer that I can stay anonymous, not because I got anything to hide, but because I don't want to pretend to be someone I'm not, like a sysadmin or I dunno. I've got too much respect for them guys who are lots more intelligent than I am, but would they ever consider to mail something as primitive as I suggest to LG? It really is a matter of getting started for unexperienced users, finding that GNU/Linux gets even more powerful while sorting it all out. So just put it in "Clueless at the prompt" or where You like. Sign with Your name, You knew the trick anyway, didn't You?
Finding What You Want with find
Date: Wed, 12 Nov 1997 16:14:43 +0000 (GMT)
From: Jon Rabone [email protected]
In the October 97 issue, Dave Nelson suggests using
find . -type f -exec grep "string" /dev/null {} \;
to persuade grep to print the filenames that it finds the search
expression in. This starts up a grep for each file, however. A shorter and
more efficient way of doing it uses backticks:
grep "string" `find . -type f`
Note however, that if the find matches a large number of files you may exceed a command line buffer in the shell and cause it to complain.
Cutting and Pasting without a Mouse
From: [email protected]
Date: Wed, 5 Nov 1997 18:58:41 +0100
It is possible, I did think there was no way but there is a way to cut and paste without any mouse. Just use screen-3.6x to achieve what you may have wanted for a long time. you use screen already but did you know how to use this cut-and-paste tool?
This was pasting without leaving your keyboard for a while!
Control-a can be any key to achieve a screen-3.6 command. There are many more very useful features with screen but i guess that like me there are people out there who may not know this very useful feature. Another hint: It is really worth printing the Manual. If like me you are going by train you can read the Manual x. I found out there are so many important features in so many programs I did not know and that did help me a lot after discovering.
About vim and completion: there is a feature that lets you complete words which you did write before which is very, very useful. press control-n in Insert-mode and vim will complete your word if you typed it before. It is even better: You can get vim to complete words that are in a different file. Just tell vim what the name of the file is with :set dictionary=file Then complete the word with control-x-control-k. Now imagine how much easier it may be to get a list of words with a grep command than to write down all kinds of abbreviations and put them into a file. This is a Killer-feature IMO!
About emacs and completion:
Emacs was first with completion or at least this kind of completion mentioned for vim goes back to 1992. What you need is hippie-exp.el which can perform all kinds of completion.
About atchange
There is a very nice script out there written in perl. I like it very much because it lets you perform an action whenever you change the date of a file. The action can be almost anything like calling another program and executing things or whatever you want. The idea came from Tom Schneider who has a page about atchange out there: http://www-lmmb.ncifcrf.gov/~toms/atchange.html
I strongly encourage you to read it, this is an idea, that can really save your time. The perl-script itself is only 68 lines of code. almost one half is explanation, the most important thing is the idea itself but Tom has a good page. So I don't tell you more right now :)
Slow Modem
Date: Mon, 3 Nov 1997 17:45:13 -0600 (CST)
From:Michael J. Hammel[email protected]
To: Larry E Scheib [email protected]
In a previous message, Larry E Scheib says:
When I access a remote site with Linux my screens paint painfully slowly; a problem I don't experience with Windows95. When my modem connects under Linux it replys "Connected at 38,400", the actual speed of my modem. The modem runs off of cua1, IRQ 3.
I'm not very good at debugging modem connections. I've never really had any problems with my dial-ups except when the network itself is bogged down. To be honest, I have no idea how fast my modem connections are actually running. I just know they're tolerable (they actually seem to run quite fast - I have a 33.6 modem).
Things that might affect this would be:
Finding Strings with find
Date: Tue, 28 Oct 1997 16:31:47 +0100
From: Gordon Walker [email protected]
Being new to Linux I find the Tips section very useful in general and the tip about searching for a string with find inspired me to write my first conditional Bash script. It finds a string in the current or given directory
#!/bin/sh
## Recursively finds all strings in given or current directory
## Usage string_search <dir> <string> (dir is optional)
## For example: "string_search fish " finds string "fish" in current
directory
## and "string_search /water fish " finds string "fish" in directory
/water
if [ "$2" = "" ]; then
find . -type f -exec grep "$1" /dev/null {} \;
else
find $1 -type f -exec grep "$2" /dev/null {} \;
fi
Another Calculator Tip
From: Frank Damgaard [email protected]
Date: Thu, 23 Oct 1997 22:05:14 +0200 (METDST)
In issue 21 there was a smart perl based command line calculator, here is another one.
I have for some years used a simple alias for the calculator command. The alias only requires awk, and that tcsh (or csh) is the running shell. This alias will not work with bash/sh/ksh since these shells do not allow arguments in aliases.
Just place the following line in your ~/.tcshrc or type at the prompt:
alias calc 'awk "BEGIN{ print \!* }" '
# When calling calc do not escape "*":
# Example: calc (3+5)*4/5
Upgrading a Laptop Hard Disk
Date: Fri, 24 Oct 1997 14:38:58 -0400
From: Peter Teuben [email protected]
I wanted to upgrade the harddisk of my laptop, which had gotten a bit tight with 800Mb and maintaining both linux and W95 (don't ask).
I got a new 2Gb drive, and of course wanted to install W95 as well as linux. I decided, despite my die-hard Slackware, to try RedHat4.2 for linux and basically "copying" W95. Since the laptop is on a local ethernet at home, I could make a backup of W95 on the desktop, and after linux was braught up, restore W95 back over the network. Indeed this worked quite nice, but you have to remember a few tricks. Here were my basic steps:
umount /DOS
insmod vfat
mount -t vfat /dev/hda1 /DOS
Caveat: For FAT32 versions of W95 (from OSR2 or W98) you may need to patch the 2.1.x kernels to include this.
Wallpaper
Date: Mon, 27 Oct 1997 14:38:35 +0100
From: Roger Irwin [email protected]
Use netscape, got xv?
Try running this script in your home directory:
rm -f XVbaa for foo in .netscape/cache/* do for baa in $foo/*.gif do echo $baa >>XVbaa done done xv -root -quit -random -flist XVbaa
This will make you a custom wallpaper on the fly by fishing in netscapes cache.
I mapped this to my fvwm2 button bar by using the following lines in .fvwm2rc95:
*FvwmButtons(Title Mood, Icon exit.xpm, \
Action 'Exec XVchange ')
This goes in the FVWM buttons section in the middle of the other lines that define the other buttons.... When I hit the Mood button, the wallpaper changes. I suppose a lazier person might use crontab....
PostScript
Date: Sun, 9 Nov 1997 22:00:31 +0000 (GMT)
From: Ivan Griffin [email protected]
Counting the Number of Pages in a file
To count the number of pages in a PostScript file, you are relying on the creator of the file to have been a sociable application and to have followed the Adobe Document Structuring Conventions (ADSC). These conventions entail the automatic placement of comments (%%) in the PostScript source so that additional applications will find it easier (and indeed, possible!) to post-process the PostScript without having to interpret it. They are generally ignored by PostScript interpreters and printers. The comment '%%Page:' delimits each new page. So to count the number of pages in a DSC compliant PostScript file, all you have to do is grep for the number of '%%Page:' markers:
grep -c '%%Page:' filename.psI generally tend to alias this to pspage in my .cshrc
alias pspage 'grep -c %%Page:'
Printing 2up
The utility pstops, part of the psutils package, allows you to process a PostScript file to enable 2up printing. I find the following works for A4 (European) paper -- the measurements will need to be tweaked for US Letter:
alias psdouble 'pstops "2:[email protected](21cm,0)[email protected](21cm,14.85cm)"'
To use it, it is as simple as:
psdouble < 1up.ps > 2up.ps
Microsoft Ugly PostScript
Quite often in PostScript generated by the Microsoft Windows driver, it requires the interpreter to have 30MB of memory, and refuses to print otherwise!! This is quite incredible, and I have found that it always seems to print perfectly well if this artifical limit is removed. The PostScript in question is:
/VM? {vmstatus exch sub exch pop gt { [ (This job requires more memory than is available in this printer.) 100 500 (Try one or more of the following, and then print again:) 100 485 (In the PostScript dialog box, click Optimize For Portability.) 115 470 (In the Device Options dialog box, make sure the Available Printer Memory is accurate.) 115 455 (Reduce the number of fonts in the document.) 115 440 (Print the document in parts.) 115 425 12 /Times-Roman showpage (%%[ PrinterError: Low Printer VM ]%%) = true FatalErrorIf}if} bind def 30000 VM?
The line "30000 VM?" checks that (roughly) 30MB of memory is available in the printer. Deleting this line is sufficient to ensure that the check is not performed, and that the job will now print (or be interpreted successfully in ghostview for example).
Linux Virtual Console Key Sequences
Date: Sun, 9 Nov 1997 22:00:31 +0000 (GMT)
From: Ivan Griffin [email protected]
Pressing these key sequences on a VC will dump information to the screen.
Displaying task information:
Ctrl-Scroll Lock gives:
free sibling task PC stack pid father child younger older swapper 0 R current 4096 0 0 1 init 1 S FFFFFFFF 2676 1 0 706 kflushd 2 S 00000000 3984 2 1 3 kswapd 3 S 00000000 3976 3 1 4 2 nfsiod 4 S 00000000 3520 4 1 5 3 nfsiod 5 S 00000000 3520 5 1 6 4 nfsiod 6 S 00000000 3520 6 1 7 5 nfsiod 7 S 00000000 3520 7 1 21 6 bash 8 S 00000000 3012 172 164 711 login 9 S 00000000 2820 164 1 172 166 135 kerneld 10 S 00000000 3224 21 1 76 7 login 11 S 00000000 3012 706 1 712 571 syslogd 12 S FFFFFFFF 3192 76 1 85 21 klogd 13 R 00000000 3404 85 1 96 76 crond 14 S 00000000 3480 96 1 108 85 inetd 15 S FFFFFFFF 3464 108 1 119 96 lpd 16 S FFFFFFFF 3376 119 1 135 108 gpm 17 S 000B206C 3368 135 1 164 119 vi 18 S FFFFFFFF 3012 711 172 mingetty 19 S FFFFFFFF 3012 166 1 167 164 bash 20 S 00000000 3012 712 706 724 httpd 21 S 00000000 3460 573 571 574 httpd 22 S 00000000 3600 574 571 575 573 httpd 23 S 00000000 3308 571 1 579 706 171 httpd 24 S 00000000 3600 575 571 576 574 mingetty 25 S FFFFFFFF 3012 167 1 168 166 mingetty 26 S FFFFFFFF 3012 168 1 169 167 mingetty 27 S FFFFFFFF 3012 169 1 171 168 httpd 28 S 00000000 3600 576 571 577 575 update 29 S 00000000 3460 171 1 571 169 httpd 30 S 00000000 3600 577 571 579 576 vi 31 S FFFFFFFF 3012 724 712 httpd 32 S 00000000 3600 579 571 577
Displaying Memory Information
Shift-Scroll Lock gives:
Mem-info: Free pages: 3136kB ( 4*4kB 0*8kB 1*16kB 1*32kB 0*64kB 24*128kB = 3136kB) Swap cache: add 0/0, delete 231912/0, find 0/0 Free swap: 16596kB 5120 pages of RAM 789 free pages 449 reserved pages 2572 pages shared Buffer memory: 2324kB Buffer heads: 2340 Buffer blocks: 2324 Buffer[0] mem: 1953 buffers, 10 used (last=1953), 0 locked, 0 protected, 0 dirty 0 shrd Buffer[2] mem: 337 buffers, 25 used (last=337), 0 locked, 0 protected, 0 dirty 0 shrd Buffer[4] mem: 3 buffers, 3 used (last=3), 0 locked, 0 protected, 3 dirty 0 shrdSize [LAV] Free Clean Unshar Lck Lck1 Dirty Shared 512 [ 0]: 0 0 0 0 0 0 0 1024 [ 186]: 31 1953 0 337 0 3 0 2048 [ 0]: 0 0 0 0 0 0 0 4096 [ 0]: 0 0 0 0 0 0 0 8192 [ 0]: 0 0 0 0 0 0 0
Netscape Hidden "Easter Eggs"
Date: Sun, 9 Nov 1997 22:00:31 +0000 (GMT)
From: Ivan Griffin [email protected]
These special URLs do interesting things in Netscape Navigator and Communicator.
about:cache gives details on your cache about:global gives details about global history about:memory-cache about:image-cache about:document about:hype about:plugins about:editfilenew view-source:URL opens source window of the URL
Ctrl-Alt-F take you to an interesting site :-)
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