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A quick way to find and delete empty dirs, it starts in the current working directory.
If you do find . -empty -type d you will see what could be removed, or to a test run.
The 00:11:22:33:44:55 is whatever you want your new MAC address to be. Sometimes sudo should be used in front if you need to.
I use this with cron to timeshift radio programs from a station's live stream.
You will get an error message at the end like "curl: (28) Operation timed out after 10000 milliseconds with 185574 bytes received"; to suppress that but not other error messages, you can append "2>&1 | grep -v "(28)"" to the end of the command.
tired of switching to the console to check if some command has finished yet? if notify-send does not work on your box try this one... e.g. rsync -av -e /usr/bin/lsh $HOME slowconnection.bar:/mnt/backup ; z (now fire up X, do something useful, get notified if this stuff has finished).
So I had this 2TB Seagate external disk/USB enclosure which by default would spin-down its internal drive (it enters a standby mode) after four minutes of inactivity.. Spinning-up the inactive drive was an annoying delay when accessing files and also it severely interfered with NFS.. SCT stands for "Standby Condition Timer".
To completely disable SCT:
$ sdparm --clear STANDBY -6 /dev/sdb
To return to original (default) SCT settings:
$ sdparm -D -p 0x1a -6 /dev/sdb
To verify the settings (before and after):
$ sdparm -a /dev/sdb
No need for vendor-provided MSWIN tools, etc.
Just one character longer than the sed version ('FNR==5' versus -n 5p). On my system, without using "exit" or "q", the awk version is over four times faster on a ~900K file using the following timing comparison:
$ testfile="testfile"; for cmd in "awk 'FNR==20'" "sed -n '20p'"; do echo; echo $cmd; eval "$cmd $testfile"; for i in {1..3}; do time for j in {1..100}; do eval "$cmd $testfile" >/dev/null; done; done; done
Adding "exit" or "q" made the difference between awk and sed negligible and produced a four-fold improvement over the awk timing without the "exit".
For long files, an exit can speed things up:
$ awk 'FNR==5{print;exit}'
This takes a webcam picture every everytime the mouse is moved (waits 10 seconds between checking for movement) and stores the picture wherever you want it.
Ideas:
Use in conjunction with a dropbox type application to see who is using your computer
Use /dev/input/mice if /dev/input/mouse* doesn't work
Use the bones of this to make a simple screensaver
opposite of https://www.commandlinefu.com/commands/view/10014/urldecoding-with-one-pure-bash-builtin ;-)
You might want to secure your AWS operations requiring to use a MFA token. But then to use API or tools, you need to pass credentials generated with a MFA token.
This commands asks you for the MFA code and retrieves these credentials using AWS Cli. To print the exports, you can use:
`awk '{ print "export AWS_ACCESS_KEY_ID=\"" $1 "\"\n" "export AWS_SECRET_ACCESS_KEY=\"" $2 "\"\n" "export AWS_SESSION_TOKEN=\"" $3 "\"" }'`
You must adapt the command line to include:
* $MFA_IDis ARN of the virtual MFA or serial number of the physical one
* TTL for the credentials