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Two command output
Summarize established connections after netstat output. Using tee and /dev/stderr you can send one command output to terminal before executing wc so you can summarize at the bottom of the output.

What is my public IP-address?
Very effective, use only DNS protocol. The @ part is optional if you already set opendns servers as default ns servers.

Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

du with colored bar graph
A more efficient way, with reversed order to put the focus in the big ones.

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

Generate a (compressed) pdf from images
use imagemagik convert

Hex math with bc
To do hex to binary: echo 'ibase=16; obase=2; 16*16' | bc # prints: 111100100 To do 16*16 from decimal to hex: echo 'ibase=10; obase=16; 16*16' | bc # prints: 100 You get the idea... Alternatively, run bc in interactive mode (see man page)

Update zone file Serial numbers
Will edit *.db files in the same directory with todays date. Useful for doing a mass update to domains on a nameserver, adding spf records, etc. Looks for a string starting with 200 or 201 followed by 7 numbers, and replaces with todays date. This won't overwrite Ip's but i would still do some double checking after running this. Make sure your server's date is correct, otherwise insert your own serial number. $rndc reload should usually follow this command.

Network Proxy to dump the application level forward traffic in plain text in the console and in a file.
If you have a client that connects to a server via plain text protocol such as HTTP or FTP, with this command you can monitor the messages that the client sends to the server. Application level text stream will be dumped on the command line as well as saved in a file called proxy.txt. You have to change 8080 to the local port where you want your client to connect to. Change also 192.168.0.1 to the IP address of the destination server and 80 to the port of the destination server. Then simply point your client to localhost 8080 (or whatever you changed it to). The traffic will be redirected to host 192.168.0.1 on port 80 (or whatever you changed them to). Any requests from the client to the server will be dumped on the console as well as in the file "proxy.txt". Unfortunately the responses from the server will not be dumped.

ls -hog --> a more compact ls -l
I often deal with long file names and the 'ls -l' command leaves very little room for file names. An alternative is to use the -h -o and -g flags (or together, -hog). * The -h flag produces human-readable file size (e.g. 91K instead of 92728) * The -o suppresses the owner column * The -g suppresses the group column Since I use to alias ll='ls -l', I now do alias ll='ls -hog'


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