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swap out "80" for your port of interest. Can use port number or named ports e.g. "http"
Parses /etc/group to "dot" format and pases it to "display" (imagemagick) to show a usefull diagram of users and groups (don't show empty groups).
or
echo '127.0.0.1 facebook.com' | sudo tee -a /etc/hosts
Do not execute this command if you don't know what you are doing.
Sorts a character string, using common shell commands.
Tells sort to ignore all characters before the Xth position in the first field per line. If you have a list of items one per line and want to ignore the first two characters for sorting purposes, you would type "sort -k1.3". Change the "1" to change the field being sorted. The decimal value is the offset in the specified field to sort by.
This command will lock the hardware eject button of your cdrom drive. Some uses are:
1: If you have a toddler and has discovered the cdrom button
2: If you are carrying a laptop in a bag or case and don't want it to eject if the button is inadvertently pressed.
To unlock the button use:
$ eject -i 0
Creates files in $DATE and hardlinks existing files to $PREVDATE. Thus full backup in each directory. Only drawback is changed modification time. Recommend a wrapper script to determine $DATE and $PREVDATE. Works like a charm. (Dirvish handrolled)
# s = combine multiple lines of whitespace into 1
# x4 = set the tabstop to 4 instead of 8
# F = Exit if the output fits on 1 screen. This is similar to git diff
# R = Raw control chars. This allows you to pipe colordiff straight to less. ie: alias sdi="svn diff | colordiff | less"
# S = Chop off long lines
# X = Dont send termcap init and deinit scrings to the terminal
Overwrites the boot sector. Since this doesn't overwrite any data, you can usually recover by re-creating the partition table exactly the same as before you zeroed it. This can also help sometimes if you install a new drive in a Windows machine which can't read it.