Commands by ptman (1)

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Use tee + process substitution to split STDOUT to multiple commands
Using process substitution, we can 'trick' tee into sending a command's STDOUT to an arbitrary number of commands. The last command (command4) in this example will get its input from the pipe.

Compare prices in euro of the HTC Desire on all the european websites of Expansys.
You think Expansys in all these countries will sell the HTC Desire for the same price? Well, you'll be surprised. Most of them will be sold at 499.99 EUR but the cheapest can be found in Germany and the most expensive, in Belgium.

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"

list block devices
Shows all block devices in a tree with descruptions of what they are.

Merge tarballs
Requires the GNU tar ignore zeros option. http://www.gnu.org/software/tar/manual/html_section/Blocking.html

Create a mirror of a local folder, on a remote server
Create a exact mirror of the local folder "/root/files", on remote server 'remote_server' using SSH command (listening on port 22) (all files & folders on destination server/folder will be deleted)

Change the primary group of a user

Display a block of text with AWK
I find this terribly useful for grepping through a file, looking for just a block of text. There's "grep -A # pattern file.txt" to see a specific number of lines following your pattern, but what if you want to see the whole block? Say, the output of "dmidecode" (as root): $ dmidecode | awk '/Battery/,/^$/' Will show me everything following the battery block up to the next block of text. Again, I find this extremely useful when I want to see whole blocks of text based on a pattern, and I don't care to see the rest of the data in output. This could be used against the '/etc/securetty/user' file on Unix to find the block of a specific user. It could be used against VirtualHosts or Directories on Apache to find specific definitions. The scenarios go on for any text formatted in a block fashion. Very handy.

simple backup with rsync
With this cron, rsync begins to sinchronize the contents of the local directory on /[VIPdirectory] with the directory /backup/[VIPdirectory] on the remote server X.X.X.X. Previously we need working on public/private-keys ssh to guarantee the acces to the remote server on X.X.X.X

check open ports without netstat or lsof


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