Commands by jtopian (1)

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Download all PDFs from an authenificated website
Replace *** with the appropiate values

Calculating series with awk: add numbers from 1 to 100
"seq 100" outputs 1,2,..,100, separated by newlines. awk adds them up and displays the sum. "seq 1 2 11" outputs 1,3,..,11. Variations: 1+3+...+(2n-1) = n^2 $ seq 1 2 19 | awk '{sum+=$1} END {print sum}' # displays 100 1/2 + 1/4 + ... = 1 $ seq 10 | awk '{sum+=1/(2**$1)} END {print sum}' # displays 0.999023

List open TCP/UDP ports

Get list of servers with a specific port open
Change the -p argument for the port number. See "man nmap" for different ways to specify address ranges.

Find the package that installed a command

Optimal way of deleting huge numbers of files

Limit bandwidth usage by apt-get
Limits the usage of bandwidth by apt-get, in the example the command will use 30Kb/s ;) It should work for most apt-get actions (install, update, upgrade, dist-upgrade, etc.)

Dump android contacts, sms
Crude, but works. Note for security, /data/ will be inaccessible unless your device has been *rooted*. On the other hand, if a device has been rooted, its data is now wide open to anyone with a USB cable and the above "one-liner". `adb` is one of the platform tools in the android SDK. To get SMS messages: $ adb pull /data/data/com.android.providers.telephony/databases/mmssms.db ; sqlite3 -batch

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"

Find out how old a web page is
I is for headers only s is for silence curl -Is outputs ONLY headers the pipe and grep is to filter them to Modified only..


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