Commands using xargs (769)

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check open ports without netstat or lsof

Top ten (or whatever) memory utilizing processes (with children aggregate)
This command loops over all of the processes in a system and creates an associative array in awk with the process name as the key and the sum of the RSS as the value. The associative array has the effect of summing a parent process and all of it's children. It then prints the top ten processes sorted by size.

port scan using parallel
It takes over 5 seconds to scan a single port on a single host using nmap $ time (nmap -p 80 192.168.1.1 &> /dev/null) real 0m5.109s user 0m0.102s sys 0m0.004s It took netcat about 2.5 minutes to scan port 80 on the class C $ time (for NUM in {1..255} ; do nc -w 1 -z -v 192.168.1.${NUM} 80 ; done &> /dev/null) real 2m28.651s user 0m0.136s sys 0m0.341s Using parallel, I am able to scan port 80 on the entire class C in under 2 seconds $ time (seq 1 255 | parallel -j255 'nc -w 1 -z -v 192.168.1.{} 80' &> /dev/null) real 0m1.957s user 0m0.457s sys 0m0.994s

Remote execute command as sudoer via ssh
Example: remote install an application(wine). sshpass -p 'mypssword' ssh -t mysshloginname@192.168.1.22 "echo 'mypassword' | sudo -S apt-get install wine" Tested on Ubuntu.

Rename files in batch

Filter the output of a file continously using tail and grep
The OPs solution will work, however on some systems (bsd), grep will not filter the data, unless the --line-buffered option is enabled.

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

list files recursively by size

Rename file to same name plus datestamp of last modification.
Note that the -i will not help in a script. Proper error checking is required.

Cropping a video file in ffmpeg


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