- WLUG - wlug.mailman3.com

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

Bash help

by Tim Trachimowicz

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

July 18, 2002

Re: [Wlug] writing to tape

by Michael Frysinger

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 >

July 18, 2002

Re: [Wlug] writing to tape

by Chuck Homic

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

July 18, 2002

writing to tape

by Brad Noyes

Hi All, I trying to write a program that will write to tape, but i can't seem to get it to work correctly. i have attached a simple piece of source code that will open a file (or device) and write the string "hello, tape". 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? Thanks, --brad

July 18, 2002

Reminder: WLUG meeting July 17th (WEDNESDAY)

by Andy Stewart

HI everybody, This month's WLUG meeting will be held on Wednesday, July 17th in Kinnicutt Hall on the WPI campus at 7:00 PM. The topic will be "Wireless Networking" and I'm pretty sure we have a speaker. If you have a laptop with a wireless connection, bring it along. I'll bring my new Linksys access point (WAP11) and my laptop. Bring whatever you think will make this an interesting meeting! After the meeting, we'll make a trip to the Boynton Restaurant for pizza and beer. I hope to see you there! Andy -- Andy Stewart, Founder Worcester Linux Users' Group Worcester, MA USA http://www.wlug.org

July 16, 2002