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determine if tcp port is open
for udp nmap -sU -p 80 hostname

Start a SOCKS proxy to avoid a restrictive firewall
You may go to Internet by means of your home ssh server. You must configure your local proxy to send traffic through the proxy. Many programs allows that: firefox, pidgin, skype, gnome, etc. Your home ssh server must listen in any of the ports permitted by your enterprise firewall. That usually includes 80 and 443.

Backup with versioning
Apart from an exact copy of your recent contents, also keep all earlier versions of files and folders that were modified or deleted. Inspired by EVACopy http://evacopy.sourceforge.net

Install a new kernel in Manjaro linux
00 is the number of the linux kernel e.g. linux39

Format partition with ext4 but without a journal
For slow flash memory (cheap thumb drive), ext4 is the fastest stable file system for all use cases with no relevant exception: http://www.linuxplanet.com/linuxplanet/tutorials/7208/1 Since we can usually dispense with the benefits of a journal for this type of storage, this is a way to achieve the least awful I/O-speed. Disabling the journal for an existing ext4 partition can be achieved using $ tune2fs -O ^has_journal /dev/sdXN Note that it is often recommended to format removable flash media with ext2, due to the lack of a journal. ext4 has many advantages over ext2 even without the journal, with much better speed as one of the consequences. So the only usecase for ext2 would be compatibility with very old software.

dd with progress bar and statistics
This command utilizes 'pv' to show dd's progress. Notes on use with dd: -- dd block size (bs=...) is a widely debated command-line switch and should usually be between 1024 and 4096. You won't see much performance improvements beyond 4096, but regardless of the block size, dd will transfer every bit of data. -- pv's switch, '-s' should be as close to the size of the data source as possible. -- dd's out file, 'of=...' can be anything as the data within that file are the same regardless of the filename / extension.

Force unmount occupied partition
Alternative if "Lazy unmount" (umount -l) doesn't obey. Alternative for NFS: $ umount -f /media/sdb1 Use with caution: forcing to unmount a busy partition can cause data loss!

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 the package that installed a command

Print a random 8 digit number


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