Commands by vasti (1)

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commandlinefu.com is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

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Find the package that installed a command

Updating the status on identi.ca using curl.
identica is an open source social networking and micro-blogging service. Based on Laconica, a micro-blogging software package built on the OpenMicroBlogging specification. http://identi.ca/

convert a line to a space

Monitor iptables in realtime

summarize a list of IP addresses, verifying IP address and giving counts for each IP found
Working with lists of IP addresses it is sometimes useful to summarize a count of how many times an IP address appears in the file. This example, summarizeIP, uses another function "verifyIP" previously defined in commandlinefu.com to ensure only valid IP addresses get counted. The summary list is presented in count order starting with highest count.

check open ports without netstat or lsof

In (any) vi, add a keystroke to format the current paragraph.
That goes into your $HOME/.exrc file. " Nice macro to reformat lines: map ^A !}fmt Note that the ^A has to be input by typing ^V^A.

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"

Block all IP addresses and domains that have attempted brute force SSH login to computer
I use iptables. To rate limit connections. Very easy and no ban lists to manage.

Find last modified files in a directory and its subdirectories
Goes through all files in the directory specified, uses `stat` to print out last modification time, then sorts numerically in reverse, then uses cut to remove the modified epoch timestamp and finally head to only output the last 10 modified files. Note that on a Mac `stat` won't work like this, you'll need to use either: $ find . -type f -print0 | xargs -0 stat -f '%m%t%Sm %12z %N' | sort -nr | cut -f2- | head or alternatively do a `brew install coreutils` and then replace `stat` with `gstat` in the original command.

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