Commands by miccaman (20)

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Get ethX mac addresses
I much prefer using /sbin/ip over /sbin/ifconfig for most everything. I find the interface and output to be much more consistent and it has many abilities that ifconfig, route, etc. do not. To get the mac address for only one interface, add 'show dev [interface]' to the 'ip link' part of the command: ip link show dev eth0 | grep 'link/ether' | awk '{print $2}' . Also, both this command and the ifconfig one do not require root access to run, so the sudo is not necessary.

Kill all processes that listen to ports begin with 50 (50, 50x, 50xxx,...)
Run netstat as root (via sudo) to get the ID of the process listening on the desired socket. Use awk to 1) match the entry that is the listening socket, 2) matching the exact port (bounded by leading colon and end of column), 3) remove the trailing slash and process name from the last column, and finally 4) use the system(…) command to call kill to terminate the process. Two direct commands, netstat & awk, and one forked call to kill. This does kill the specific port instead of any port that starts with 50. I consider this to be safer.

Loop over the days of a month, in $YYYY$MM$DD format
Edit YYYY and MM at the beginning of the command with the year and month you want. Note that `DD=$(printf "%02d" $d)` will pad single digit integers with a leading zero. Substitute `echo $YYYY$MM$DD` at the end of the line with the command you want to launch, for instance script.pl --yyyymmdd $YYYY$MM$DD Also available on GitHub as bash util: https://github.com/fibo/yyyymmdd

Get your outgoing IP address
Get your external ip adress thanks to http://www.icanhazip.com

Awk: Perform a rolling average on a column of data
Sometimes jittery data hides trends, performing a rolling average can give a clearer view.

Find the package that installed a command

Find ASCII files and extract IP addresses

Clean up poorly named TV shows.
Replace 'SHOWNAME' with the name of the TV show. Add -n to test the command without renaming files. Check the 'sample output'.

Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

Remove invalid key from the known_hosts file for the IP address of a host
Quick shortcut if you know the hostname and want to save yourself one step for looking up the IP address separately.


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