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Console clock
Shows a simple clock in the console -t param removes the watch header Ctrl-c to exit

list ips with high number of connections

Check apache config syntax and restart or edit the file
Checks the apache configuration syntax, if is OK then restart the service otherwise opens the configuration file with VIM on the line where the configuration fails.

Execute a command at a given time
This is an alternative to cron which allows a one-off task to be scheduled for a certain time.

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"

Concatenate video files to YouTube ready output
Takes two input video files and an external audio track and encodes them together to an MPEG-4 DivX output video file with the correct size ready for uploading.

Browse system RAM in a human readable form
This command lets you see and scroll through all of the strings that are stored in the RAM at any given time. Press space bar to scroll through to see more pages (or use the arrow keys etc). Sometimes if you don't save that file that you were working on or want to get back something you closed it can be found floating around in here! The awk command only shows lines that are longer than 20 characters (to avoid seeing lots of junk that probably isn't "human readable"). If you want to dump the whole thing to a file replace the final '| less' with '> memorydump'. This is great for searching through many times (and with the added bonus that it doesn't overwrite any memory...). Here's a neat example to show up conversations that were had in pidgin (will probably work after it has been closed)... $sudo cat /proc/kcore | strings | grep '([0-9]\{2\}:[0-9]\{2\}:[0-9]\{2\})' (depending on sudo settings it might be best to run $sudo su first to get to a # prompt)

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"

sed : using colons as separators instead of forward slashes
Having to escape forwardslashes when using sed can be a pain. However, it's possible to instead of using / as the separator to use : . I found this by trying to substitute $PWD into my pattern, like so $ sed "s/~.*/$PWD/" file.txt Of course, $PWD will expand to a character string that begins with a / , which will make sed spit out an error such as "sed: -e expression #1, char 8: unknown option to `s'". So simply changing it to $ sed "s:~.*:$PWD:" file.txt did the trick.

Prepend a text to a file.
Using the sed -i (inline), you can replace the beginning of the first line of a file without redirecting the output to a temporary location.


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