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Auto-log commands
A quick alias I use right before logging into a server so that I have a log of the transactions as well as the ability to re-connect from another computer. Useful for when your boss says "what commands did you run again on that server?" and you had already closed the terminal ;) I wrapped it in a script now, with more features, but this is the heart of it. Never leave home without it.

cat ~/.ssh/id_rsa.pub | ssh user@site.com "cat - >> ~/.ssh/authorized_keys"
You'll want to use this for passwordless logins. Same as ssh-copy-id, if you don't have it on your system.

sync two folders except hidden files

Find usb device
I often use it to find recently added ou removed device, or using find in /dev, or anything similar. Just run the command, plug the device, and wait to see him and only him

Sharing file through http 80 port
From the other machine open a web navigator and go to ip from the machine who launch netcat, http://ip-address/ If you have some web server listening at 80 port then you would need stop them or select another port before launch net cat ;-) * You need netcat tool installed

Delete leading whitespace from the start of each line
Removes any whitespace characters at the beginning of a line.

See KeepAlive counters on tcp connections
See connection's tcp timers

Force hard reset on server
Useful when you have some wrong on a server (nfs freeze/ immortal process)

Burn an ISO on commandline with wodim instead cdrecord

Add directory to $PATH if it's not already there
Sometimes in a script you want to make sure that a directory is in the path, and add it in if it's not already there. In this example, $dir contains the new directory you want to add to the path if it's not already present. There are multiple ways to do this, but this one is a nice clean shell-internal approach. I based it on http://stackoverflow.com/a/1397020. You can also do it using tr to separate the path into lines and grep -x to look for exact matches, like this: $ if ! $(echo "$PATH" | tr ":" "\n" | grep -qx "$dir") ; then PATH=$PATH:$dir ; fi which I got from http://stackoverflow.com/a/5048977. Or replace the "echo | tr" part with a shell parameter expansion, like $ if ! $(echo "${PATH//:/$'\n'}" | grep -qx "$dir") ; then PATH=$PATH:$dir ; fi which I got from http://www.commandlinefu.com/commands/view/3209/. There are also other more regex-y ways to do it, but I find the ones listed here easiest to follow. Note some of this is specific to the bash shell.


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