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If you spend most of your time in front of the terminal, leave is a useful reminder. Leave can have absolute form: leave 1555 reminds you to leave at 3:55PM
If the first two letters are "ii", then the package is installed. You can also use wildcards. For example,
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$ dpkg -l openoffice*
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Note that dpkg will usually not report packages which are available but uninstalled. If you want to see both which versions are installed and which versions are available, use this command instead:
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$ apt-cache policy python
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"
This let's you find out the total packages that have available upgrades. Usefull if you want to check or show the total available upgrades on your system.
Same as original, but works in bash
What do you do when nmap is not available and you want to see the hosts responding to an icmp echo request ? This one-liner will print all hosts responding with their ipv4 address.
Get your colorized grep output in less(1). This involves two things: forcing grep to output colors even though it's not going to a terminal and telling less to handle those properly.
This is different that `who` in that who only cares about logged-in users running shells, this command will show all daemon users and what not; also users logged in remotely via SSH but are running SFTP/SCP only and not a shell.
Takes all the .3gp files in the directory, rotates them by 90 degrees, and saves them in the lossless ffv1 encoding.
If this rotates in the wrong direction, you may want transponse=1
Re-encoding to ffv1 may result in a significant increase in file size, as it is a lossless format. Other applications may not recognize ffv1 if they don't use ffmpeg code. "huffyuv" might be another option for lossless saving of your transformations.
The audio may be re-encoded as well, if the encoding used by your 3gp file doesn't work in a avi container.