Commands by atoponce (56)

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copy timestamps of files from one location to another - useful when file contents are already synced but timestamps are wrong.
Sometimes when copying files from one place to another, the timestamps get lost. Maybe you forgot to add a flag to preserve timestamps in your copy command. You're sure the files are exactly the same in both locations, but the timestamps of the files in the new home are wrong and you need them to match the source. Using this command, you will get a shell script (/tmp/retime.sh) than you can move to the new location and just execute - it will change the timestamps on all the files and directories to their previous values. Make sure you're in the right directory when you launch it, otherwise all the touch commands will create new zero-length files with those names. Since find's output includes "." it will also change the timestamp of the current directory. Ideally rsync would be the way to handle this - since it only sends changes by default, there would be relatively little network traffic resulting. But rsync has to read the entire file contents on both sides to be sure no bytes have changed, potentially causing a huge amount of local disk I/O on each side. This could be a problem if your files are large. My approach avoids all the comparison I/O. I've seen comments that rsync with the "--size-only" and "--times" options should do this also, but it didn't seem to do what I wanted in my test. With my approach you can review/edit the output commands before running them, so you can tell exactly what will happen. The "tee" command both displays the output on the screen for your review, AND saves it to the file /tmp/retime.sh. Credit: got this idea from Stone's answer at http://serverfault.com/questions/344731/rsync-copying-over-timestamps-only?rq=1, and combined it into one line.

Count number of hits per IP address in last 2000 lines of apache logs and print the IP and hits if hits > 20

Remove invalid host keys from ~/.ssh/known_hosts
Useful if you have to tunnel ssh through a local port and it complains of the host key being different. Much easier than manually editing the file.

bulk rename files with sed, one-liner
Far from my favorite, but works in sh and with an old sed that doesn't support '-E'

convert filenames in current directory to lowercase
The simplest way I know.

Send data securly over the net.
Using OpenSSL we can encrypt any input we wish and then use Netcat to create a socket which can be connected to from an externally source (even using a Web Browser)

Check wireless link quality with dialog box
The variable WIRELESSINTERFACE indicates your wireless interface

Deleting / Ignoring lines from the top of a file

Find the package that installed a command

Find the package that installed a command


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