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vim as a pager - similar to less command but with color
use vim like less command pager but with color highlighting = pretty :p also u can use /usr/share/vim/vim73/macros/less.sh

List top 20 IP from which TCP connection is in SYN_RECV state
List top 20 IP from which TCP connection is in SYN_RECV state. Useful on web servers to detect a syn flood attack. Replace SYN_ with ESTA to find established connections

Show what a given user has open using lsof

validate the syntax of a perl-compatible regular expression
Place the regular expression you want to validate between the forward slashes in the eval block.

Enter your ssh password one last time
Enter your ssh public key in the remote end for future key-based authentication. Just type your password one last time. The next time you should be able to login with the public key. If you don't have a key, generate one with ssh-keygen. Requires Bourne-compatible shell in the remote end.

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"

Retrieve the size of a file on a server
Downloads the entire file, but http servers don't always provide the optional 'Content-Length:' header, and ftp/gopher/dict/etc servers don't provide a filesize header at all.

Update grub menu.lst
Remove all commented lines Remove all blank lines Show the menu Up the delay so you have enough time to select a kernel Remove the quiet so you can watch the entire boot Add a rootdelay for san attached storage booting

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.

Resize all JPEGs in a directory
This command requires the imagemagick libraries and will resize all files with the .jpg extension to a width of 1024 pixels and will keep the same proportions as the original image.


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