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Show git branches by date - useful for showing active branches
Print out list of all branches with last commit date to the branch, including relative time since commit and color coding.

Display the end of a logfile as new lines are added to the end

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" }

Get Cookies from bash
The loop is to compare cookies. You can remove it... Maybe you wanna use curl... $ curl www.commandlinefu.com/index.php -s0 -I | grep "Set-Cookie"

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)

Read and write to TCP or UDP sockets with common bash tools
Ever needed to test firewalls but didn't have netcat, telnet or even FTP? Enter /dev/tcp, your new best friend. /dev/tcp/(hostname)/(port) is a bash builtin that bash can use to open connections to TCP and UDP ports. This one-liner opens a connection on a port to a server and lets you read and write to it from the terminal. How it works: First, exec sets up a redirect for /dev/tcp/$server/$port to file descriptor 5. Then, as per some excellent feedback from @flatcap, we launch a redirect from file descriptor 5 to STDOUT and send that to the background (which is what causes the PID to be printed when the commands are run), and then redirect STDIN to file descriptor 5 with the second cat. Finally, when the second cat dies (the connection is closed), we clean up the file descriptor with 'exec 5>&-'. It can be used to test FTP, HTTP, NTP, or can connect to netcat listening on a port (makes for a simple chat client!) Replace /tcp/ with /udp/ to use UDP instead.

Restrict the bandwidth for the SCP command
the command is obvious, I know, but maybe not everyone knows that using the parameter "-l" you can limit the use of bandwidth command scp. In this example fetch all files from the directory zutaniddu and I copy them locally using only 10 Kbs

Analyse an Apache access log for the most common IP addresses
This uses awk to grab the IP address from each request and then sorts and summarises the top 10.

Replace + Find

ASCII art of yourself
Use libcaca to render ascii chars on the webcam input... or don't.


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