Commands using echo (1,545)

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print java packages by using unix tree and sed
if you need a quick way of printing out all the packages that contain classes this command will print the directory structure and replace '/' with '.' It will also ignore CVS directories (we use CVS here)

Print all open regular files sorted by the number of file handles open to each.
List all open files of all processes. . $ find /proc/*/fd Look through the /proc file descriptors . $ -xtype f list only symlinks to file . $ -printf "%l\n" print the symlink target . $ grep -P '^/(?!dev|proc|sys)' ignore files from /dev /proc or /sys . $ sort | uniq -c | sort -n count the results . Many processes will create and immediately delete temporary files. These can the filtered out by adding: $ ... | grep -v " (deleted)$" | ...

Recursively grep for string and format output for vi(m)
This is a big time saver for me. I often grep source code and need to edit the findings. A single highlight of the mouse and middle mouse click (in gnome terminal) and I'm editing the exact line I just found. The color highlighting helps interpret the data.

Find all folder in /var that contains log in their path and have more than 10 files inside them, print the folder and the count
-L is for following symbolic links, it can be omitted and then you can find in your whole / dir

Convert YAML to JSON
* Output is jq compatible * Output is single lines - unix compatible * Multiple files supported

Create md5sum of files under the current dir excluding some directories
Useful if you want get all the md5sum of files but you want exclude some directories. If your list of files is short you can make in one command as follow: $ find . -type d \( -name DIR1 -o -name DIR2 \) -prune -o -type f -exec md5sum {} \; Alternatively you can specify a different command to be executed on the resulting files.

Block all IP addresses and domains that have attempted brute force SSH login to computer
Searches all log files (including archived bzip2 files) for invalid user and PAM authentication errors, both of which are indicative of brute force attempts at logging into computer. A list of all unique IP addresses and domain names is appended to hosts.deny. The command (and grep error messages) will work on Mac OS X 10.6, small adjustments may be needed for other OSs.

shutdown if wget exit

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"

Check if a machine is online with better UI
I have used single packet, and in a silent mode with no display of ping stats. This is with color and UI improvement to the http://www.commandlinefu.com/commands/view/10220/check-if-a-machine-is-online. It is as per the enhancements suggested.


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