July 2002 - WLUG - wlug.mailman3.com

Question about WLUG BBQ

by Andy Stewart

Hi WLUG, We had a suggestion last night over a few beers that perhaps we could conduct our next Linux meeting in Shrewsbury over a few BBQd burgers, dogs, etc. What do people think of that idea? If this idea is accepted by enough folks, it would be held on the same day and time as our next regularly scheduled meeting. What do folks think of this proposal? Later, Andy -- Andy Stewart, Founder Worcester Linux Users' Group Worcester, MA USA http://www.wlug.org

July 19, 2002

Re: [Wlug] writing to tape

by Brad Noyes

THANKS!!! the problem was solved by writing/reading in 512 byte chucks. I did try serveral different flags to open(), and they seemed to work. thanks chuck and michael, --brad On Wed, Jul 17, 2002 at 09:03:27PM -0400, Michael Frysinger wrote: > try to get rid of the O_TRUNC to see if it might help > <from `man dd`> > Often a tape drive will not accept arbitrarily sized blocks, > and dd would get an I/O error for the last fragment of data > that does not fill an entire block. Use `dd if=myfile of=/dev/mytape > conv=sync' to get everything on tape. Of course, reading it back > will now produce a slightly larger file, with nulls added at the end. > </from `man dd`> > -mike > > ----- Original Message ----- > From: "Chuck Homic" <chuck(a)vvisions.com> > To: <wlug(a)mail.wlug.org> > Sent: Wednesday, July 17, 2002 8:46 PM > Subject: Re: [Wlug] writing to tape > > > > On Wed, Jul 17, 2002 at 08:36:16PM -0400, Brad Noyes wrote: > > > This program will work with a file, and a floppy device, but not a tape > > > device. > > > > > > can anyone give me some pointers? what do i have to do differently to > > > write to tape? > > > > I've never used tape before, but I know tape is not quite as ambidextrous > > as a file or floppy device. > > > > So, instead of O_RDWR | O_CREAT | O_TRUNC, I'd try a simple O_WRONLY. Or > > other things. Maybe. > > > > -Chuck > > _______________________________________________ > > Wlug mailing list > > Wlug(a)mail.wlug.org > > http://mail.wlug.org/mailman/listinfo/wlug > > > > _______________________________________________ > Wlug mailing list > Wlug(a)mail.wlug.org > http://mail.wlug.org/mailman/listinfo/wlug

July 19, 2002

Thanks!

by Tim Trachimowicz

Hey folks! Thanks for multiple answers to my question. I ended up using Theo's solution: for i in *_x.*; do mv -f $i `echo $i | sed -e 's/_x././'`; done and it worked perfectly to get the job done. I've since been playing around with a few of the other suggestions to see what would work best next time I need to do soemthing similar. If anything, it's sparked my interest to learn more about shell scripting. Thanks again! --Tim

July 18, 2002

Re: [Wlug] Bash help

by Charles R. Anderson

On Thu, Jul 18, 2002 at 10:04:40AM -0400, Josh Huber wrote: huber> And, here's yet another way of doing it, if you have mmv installed. huber> (mmv is cool!) huber> huber> $ mmv "*_x.*" "#1.#2" util-linux comes with "rename", which wil work IF the extension is always the same and there is only the one dot in the filename: rename '_x.' '.' *_x.* -- Charles R. Anderson <cra(a)wpi.edu> / http://angus.ind.wpi.edu/~cra/ PGP Key ID: 49BB5886 Fingerprint: EBA3 A106 7C93 FA07 8E15 3AC2 C367 A0F9 49BB 5886

July 18, 2002

Re: [Wlug] Bash help

by Frank Sweetser

On Thu, Jul 18, 2002 at 10:04:40AM -0400, Josh Huber wrote: Bad Josh! you didn't post from the address you're subscribed with! no cookie for you... -- Frank Sweetser fs at wpi.edu, fs at suave.net | $ x 18 Full-time WPI Network Engineer, Part time Linux/Perl guy | > I was wondering why the ext2fs filesystems was developed for Linux >rather than using the BSD4.4 Berkeley Fast Filesystem. Because it was a real fun to design and program it... -- Remy Card

July 18, 2002

Re: [Wlug] Bash help

by Josh Huber

Skip Gaede <sgaede(a)attbi.com> writes: > Here's yet another way of doing it, by using bash builtins: And, here's yet another way of doing it, if you have mmv installed. (mmv is cool!) $ mmv "*_x.*" "#1.#2" Also, mmv is pretty good about checking for stupid things, like trying to move all the files in a directory into 1 file. -- Josh Huber

July 18, 2002

Re: [Wlug] Bash help

by Skip Gaede

On Wednesday 17 July 2002 23:47, Tim Trachimowicz wrote: > Hey folks! > > I have a bunch of files on a server that are in the > format "filename_x.dat" and I need to rename them > "filename.dat", i.e. strip to last two characters off the > filename while maintaining the extension. > Here's yet another way of doing it, by using bash builtins: for _file in $(ls *_x.*); do _front=${_file%\_*} _back=${_file#*\.} mv $_file $_front.$_back done; The code may need to be tweaked slightly to deal with multiple underscores or multiple dots in the filename, and if they all end in .dat, then the logic is even simpler. --Skip

July 18, 2002

Re: [Wlug] Bash help

by Aaron Haviland

Scott Venier said: > for i in * ; do > mv $i `echo $i | sed 's/$.*$..\.$.*$/\1.\2/'` > done I realise it's probably of little concern when dealing with files, but some 1000 calls to sed vs. using a bash-builtin makes for a huge difference in speed: [orion@tribble(~)] TEXT="stuff to work with" [orion@tribble(~)] time for i in $(seq 1 1000); do OTHER=$(echo $TEXT | sed "s/work/goosnargh/g"); done; echo $OTHER real 0m19.405s user 0m5.010s sys 0m12.310s stuff to goosnargh with [orion@tribble(~)] time for i in $(seq 1 1000); do OTHER=${TEXT/work/goosnargh};done; echo $OTHER real 0m0.204s user 0m0.180s sys 0m0.000s stuff to goosnargh with there's quite a few other builtins that can almost replace sed and cut in most situations. look in bash's manpage under "Parameter Expansion" :) -- Aaron Haviland orion [at] tribble [dot] dyndns [dot] org orion [at] parsed [dot] net Can I get 1 bpm by flashing a mirror?

July 18, 2002

Re: [Wlug] Bash help

by Theo Van Dinter

On Wed, Jul 17, 2002 at 08:47:35PM -0700, Tim Trachimowicz wrote: > I have a bunch of files on a server that are in the > format "filename_x.dat" and I need to rename them "filename.dat", i.e. > strip to last two characters off the filename while maintaining the > extension. Are they all "_x"? You could do something like: for i in *_x.*; do mv -f $i `echo $i | sed -e 's/_x././'`; done it would be more flexible to do in perl of course: opendir(T,".") || die "can't open dir:$!"; while($_=readdir(T)){ next unless ( -f $_ ); ($a,$b) = /^(.+)\.(.+)$/; next unless ( $a && $b ); $a =~ s/..$//; rename($_,"$a.$b"); } closedir(T); Warning: none of these have been tested, I just wrote them out so YMMV. -- Randomly Generated Tagline: "I'm at the age where food has taken the place of sex in my life. In fact, I've just had a mirror placed over my kitchen table." - Rodney Dangerfield

July 18, 2002

Re: [Wlug] Bash help

by Scott Venier

for i in * ; do mv $i `echo $i | sed 's/$.*$..\.$.*$/\1.\2/'` done Should do the trick... It moves each file to the original filename, minus the two characters before the last . As far as a book to get, _Learning the bash Shell, 2nd Edition_, published by o'reilly. Also likely useful _sed & awk, 2nd Edition_, also published by o'reilly. The sed book will translate that example of leaning toothpick syndrome. Scott On Wed, 17 Jul 2002, Tim Trachimowicz wrote: > Hey folks! > > I have a bunch of files on a server that are in the > format "filename_x.dat" and I need to rename them "filename.dat", i.e. > strip to last two characters off the filename while maintaining the > extension. > > If it wasn't for the fact that I have about 400 files in multiple > directories, I'd do it by hand. However, it's of a somewhat urgent > nature - hence this slightly off-topic cry for help! =) > > I'm pretty sure there's a way to do it via a shell script (I use bash) - > the only problem being that I've never written one before. Can anyone > point me to a faq/tutorial/website that might explain the process? If > it's a trivial task, anyone care to take a stab? Google gave me a few > leads, but most aren't helping a lot. > > Any help is appreciated! Thanks! > > --Tim > _______________________________________________ > Wlug mailing list > Wlug(a)mail.wlug.org > http://mail.wlug.org/mailman/listinfo/wlug >

July 18, 2002