- Roundtable - muug.ca

Re: [RndTbl] script for file copy
by Adam Thompson 07 Jul '10

07 Jul '10

Umm... I think I misunderstood the original question. You want to flatten a directory structure into a single directory while preserving a record of the original path encoded in the filename. I think this would do what you want: find "${SRC}" -type f -print | while read F1; do F2=$( echo "${F1}" | tr '/' '_' ) mv "${F1}" "${F2}" done -Adam > -----Original Message----- > From: Adam Thompson [mailto:athompso@athompso.net] > Sent: Wednesday, July 07, 2010 2:09 PM > To: 'Continuation of Round Table discussion' > Subject: RE: [RndTbl] script for file copy > > I've had to do this before... there are some tools that'll do it for you, > essentially you want the UNIX version of MS-DOS's "UPDATE" command. > I would look at "rsync", used in local mode, use something like > > $ rsync -a --existing SRCDIR DSTDIR > > It is of course possible to do this in a shell script, but it's tricky to handle > the recursion correctly unless you use an iterative find/grep series, which > gets very expensive in terms of CPU time. > > The best non-recursive technique I can think of would be something like: > #!/bin/sh > SRC="$1" > DST="$2" > T1=$(mktemp) > T2=$(mktemp) > find "${SRC}" -type f -print | sed -e "s/^${SRC}//" | sort > "${T1}" > find "${DST}" -type f -print | sed -e "s/^${DST}//" | sort > "${T1}" > comm -12 "$T1" "$T2" | while read F ; do > cp "${SRCDIR}${F}" "${DSTDIR}${F}" > done > > -Adam > > > -----Original Message----- > > From: roundtable-bounces(a)muug.mb.ca [mailto:roundtable- > > bounces(a)muug.mb.ca] On Behalf Of VE4ER / Andy > > Sent: Wednesday, July 07, 2010 12:10 PM > > To: MUUG Roundtable > > Subject: [RndTbl] script for file copy > > > > Can anybody suggest a script to copy files from one directory > > structure to another changing the filename in the process to include > > the original folder names, but only if an actual file with extension > > exists in the bottom child folder : > > > > Go from : > > > > Master Folder ------> Sub Folder1 -----> Sub Sub Folder1 ---> > > filename.example > > ------> Sub Folder2 -----> Sub Sub Folder1 > > ---> filename.example > > ------> Sub Folder2 -----> Sub Sub Folder2 > > ---> filename.example > > > > > > To: > > > > /Var/MainFolder/Master_Sub1_SubSub1_filename.example > > /Var/MainFolder/Master_Sub2_SubSub1_filename.example > > /Var/MainFolder/Master_Sub2_SubSub2_filename.example > ....etc > > > > > > Thanks > > Andy > > > > _______________________________________________ > > Roundtable mailing list > > Roundtable(a)muug.mb.ca > > http://www.muug.mb.ca/mailman/listinfo/roundtable

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bash expansion question
by Adam Thompson 07 Jul '10

07 Jul '10

I can't find what I'm looking for in the bash(1) manpage, hoping there's an easy answer... I want to use a construct like for i in ~/path/*; do something $i && rm $i; done which works great as long as there are files in ~/path/. However, when the directory is empty, I get: rm: cannot remove `/home/athompso/path/*': No such file or directory which isn't quite what I want. The quick fix in this case is to use for i in ~/path/*; do [ -f $i ] && something $i && rm $i; done but once again, that strikes me as inelegant and I can't remember OR find the better way to do it. Anyone? Thanks, -Adam

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high-power 802.11g router recommendations?
by Adam Thompson 02 Jul '10

02 Jul '10

Looking for recommendations for a wireless router than has better-than-usual range. I’ve used the Buffalo WHR-HP-G54 with good results, but they’re basically impossible to find locally. I’ve also now experienced the D-Link DIR-825’s pathetic range, not sure I want to trust D-Link’s RangeBooster line without first-hand recommendations. Any suggestions? Thanks, -Adam

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Encrypt files/info/whatever easily.
by Sean Cody 01 Jul '10

01 Jul '10

So yeah this is normally something I would reserve for the newsletter but the inspiration hit me and I'll forget by September. :P So say someone wants to tell you something secret or you need to write down a secret in a file but don't want it in plaintext. Well using the shell & openssl [installed by default on OS X and probably on Linux [I know it's default on *BSD]]... Assuming your shell is SH derrivitive.. #cat << EOL | openssl aes-256-cbc -a -salt -out secret.txt OMG I haz a secretz! EOL (password will be requested here) # Notice I'm using what is referred to as a HEREDOC and piping it to openssl chosing the aes-256-cbc cipher. The -a parameter just says the input is in base64. -salt is well salting the cipher. So how do you get that back? #openssl aes-256-cbc -d -a -in secret.txt (password will be requested here) OMG I haz a secretz! # In this case -d is well... decrypt. You can replace the cat pipeline with -in somefile.txt if you want to do files themselves but this way no plaintext hits the disk (unless you shell swaps... which you have other issues then. :P). This is awesome because you don't have to install something special (ie. truecrypt) for a quick encrypt and you can store the data set anywhere and pull it (say via wget with pipelining) from random places with openssl installed to decrypt. Not really suggested for super secret stuff but it can be pretty handy... especially when passing around messages in a MacGyver sneaker net style situation. -- Sean

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restarting a process via crontab?
by athompso＠athompso.net 14 Jun '10

14 Jun '10

My server panics occasionally (bad RAM that I haven't replaced yet - it's ECC but one bank occasionally hits an uncorrectable multi-bit error), which of course leaves various state files laying around on disk without the processes to match them. In particular, fetchmail(1) is causing me problems; there's a ~/.fetchmail.pid file that's supposed to contain the PID of the running fetchmail daemon. It has to run (well, I *want* it to run) as me, not as root, so starting it from init isn't a good solution. I'd also like it to be recover gracefully if I have to kill it (or it crashes due to a bug), also contraindicating the obvious rc.local solution. So far, the best solution I've come up with is a crontab entry (for me, not root): 0 * * * * if [ -f /home/athompso/.fetchmail.pid ];then read FP</home/athompso/.fetchmail.pid;if [ -d /proc/$FP -a -r /proc/$FP/exe ];then BIN=$(stat -c %N /proc/$FP/exe);BIN="${BIN#*-> }";BIN="${BIN#\`}";BIN="${BIN%\'}";BIN=$(basename "${BIN}");if [ "$BIN" == "fetchmail" ];then exit 0;fi;fi;fi;fetchmail (or, more readably:) if [ -f /home/athompso/.fetchmail.pid ] then read FP < /home/athompso/.fetchmail.pid if [ -d /proc/$FP -a -r /proc/$FP/exe ] then BIN=$(stat -c %N /proc/$FP/exe) BIN="${BIN#*-> }" BIN="${BIN#\`}" BIN="${BIN%\'}" BIN=$(basename "${BIN}") if [ "$BIN" == "fetchmail" ] then exit 0 fi fi fi fetchmail I particularly hate the method of extracting the imagename for a given PID, but haven't come up with anything better yet. Suggestions gratefully appreciated. Or even a better way of doing this altogether; this feels like a terrible hack - it works, but doesn't seem elegant. FYI: I decided against using sed(1) to parse the output because doing it this way saves two fork(2)s and one exec(2). I know I don't need to worry about efficiency on a dual-Xeon server, but I'm trying to stay in the habit because I'm also working on 200MHz ARM5 platforms where it does matter. (And who ever thought putting the output of stat(1) in typographical-style quotes would be a good idea???) Thanks for any suggestions, -Adam

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D-Link DIR-825 dual-band 802.11N 5xGigE runs DD-WRT, for around $150
by athompso＠athompso.net 13 Jun '10

13 Jun '10

Further to my comments at the last meeting, I was pleasantly surprised when I bought a D-Link DIR-825 and discovered it can run DD-WRT. This is a *simultaneous* dual-band (i.e. two radios, one at 2.4GHz, one at 5GHz) 802.11N router with 5 GigE ports, a USB port, two antennas, and the usual array of activity lights on the front. There is a beta build of DD-WRT that runs on this unit (and thus presumably OpenWRT will also support it soon if not already). Range & performance are OK but not great. The price, however, is impressive: you can typically find it online (in Canada) for under $150. If it were a $250 unit, it would be utterly unremarkable (aside from being one of the first dual-radio models to run DD-WRT) but considering that you can still regularly find 802.11G and single-band 802.11N routers for over $150, that makes it impressive - for now. With the stock D-Link firmware, the USB port can be used for (apparently) *any* device whatsoever, and includes software to remotely connect a Windows PC to the port. Not sure how they've done this, but I'm told it should work for any USB device (subject to bandwidth limitations, of course - USB2.0 is still faster than 802.11N). DD-WRT can expose USB storage devices and (I think) printers; so you do lose something compared to the factory firmware. Flashing DD-WRT onto the device requires TFTP while putting the device into disaster-recovery mode; it was harder to find the instructions online than to actually do it. Also see CNet's review here: http://reviews.cnet.com/routers/d-link-xtreme-n/4505-3319_7-33246906.html#c… -Adam

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Re: [RndTbl] D-Link DIR-825 dual-band 802.11N 5xGigE runs DD-WRT, for around $150
by Adam Thompson 13 Jun '10

13 Jun '10

Yes, both antennas are the standard consumer-grade-router connector. In fact, you have to screw them on yourself when you unpack it :). Not sure how directional antennae play with N's beam-forming-ish tech though. -Adam

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Temperature/Humidty
by Dan Keizer 11 Jun '10

11 Jun '10

One of the questions at the muug meeting today was about temperature and humidity readings/monitoring. The 1-wire devices are quite easy to use .. there are a few links I've saved from prior here: http://delicious.com/ve4drk/1-wire -- they're about a year or so old ... an interesting take is using the owfs (http://owfs.org/) with openWRT ( http://openwrt.org/ ):-) yes -- you know it can be done :-) I know another local who has used these .. he has a nice display and info on how to do it .. it is: http://www2.ertyu.org/temp/conditions.php Dan.

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Desperate plea for help
by Kevin McGregor 07 Jun '10

07 Jun '10

I've got a HP ProLiant server running OpenFiler, and due to errors on my part, the SCSI drives got rearranged. Now the HP 6400 RAID controller complains that an "unsupported drive rearrangement has been attempted", and the logical volume is missing. Is there any way to recover the correct order of drives in the drive bay? It is a test server, so technically no big deal, but you know how it is with "test" servers... It would be pretty annoying to lose all the data. I've tried booting the 8.30 SmartStart and using the ADU/ACU utility, but it doesn't seem to show anything useful for this. It shows the controller and all drives being "uninitialized", not just being out of order. The Option ROM utility also doesn't show anything. Suggestions, aside from "use software RAID next time"? Kevin

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Replacement Shuttle PSU PC35I2402.
by Sean Cody 07 Jun '10

07 Jun '10

Anyone know of any decent place to find a replacement PSU for a Shuttle box. PSU part number is PC35I2402. It is probably not worth replacing though if there are 'off brand' options I wouldn't mind knowing a few places to search. -- Sean

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