Commands by dimentox (1)

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Tar - Compress by excluding folders
If you give tar a list of filenames, it will not add the directories, so if you don't care about directory ownership or permissions, you can save some space. Tar will create directories as necessary when extracting. This command is limited by the maximum supported size of the argument list, so if you are trying to tar up the whole OS for instance, you may just get "Argument list too long".

Execute a command with a timeout
A timeout is great, but what if the command is taking longer than expected because it's hung up or ran into some other problem? That's where the -k option comes in. Run "some_command" and timeout after 30s. If the command is still running after 1 minute, it will receive a kill signal.

Prevent an IPv6 address on an interface from being used as source address of packets.
If two or more IPv6 addresses are assigned to an interface, apply this command to all but the address that you want to use as the source address of outbound packets. This is Linux-specific and requires the iproute package, or equivalent for your distribution.

Remove a file whose name begins with a dash ( - ) character
Using the redundant ./ directory information prevents the dash from occurring at the beginning of the filename, and being interpreted as an option of the rm command. Also works using: $ rm -- -filename

DELETE all those duplicate files but one based on md5 hash comparision in the current directory tree
This one-liner will the *delete* without any further confirmation all 100% duplicates but one based on their md5 hash in the current directory tree (i.e including files in its subdirectories). Good for cleaning up collections of mp3 files or pictures of your dog|cat|kids|wife being present in gazillion incarnations on hd. md5sum can be substituted with sha1sum without problems. The actual filename is not taken into account-just the hash is used. Whatever sort thinks is the first filename is kept. It is assumed that the filename does not contain 0x00. As per the good suggestion in the first comment, this one does a hard link instead: $ find . -xdev -type f -print0 | xargs -0 md5sum | sort | perl -ne 'chomp; $ph=$h; ($h,$f)=split(/\s+/,$_,2); if ($h ne $ph) { $k = $f; } else { unlink($f); link($k, $f); }'

Find all active ip's in a subnet
nmap for windows and other platforms is available on developer's site: http://nmap.org/download.html nmap is robust tool with many options and has various output modes - is the best (imho) tool out there.. from nmap 5.21 man page: -oN/-oX/-oS/-oG : Output scan in normal, XML, s|

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"

GRUB2: Set Imperial Death March as startup tune
Kudos to http://www.commandlinefu.com/commands/view/8275/grub2-set-super-mario-as-startup-tune

Generate Sha1, MD5 hash using echo
This is mostly for my own notes but this command will compute a md5 message digest from the command line. You can also replace md5sum with other checksum commands (e.g., sha1sum)

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