Commands by eneko (6)

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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.

How to pull out lines between two patterns
This command will display all lines between 2 patterns: word-a and word-b useful for grepping command outputs from file

Run a command, redirecting output to a file, then edit the file with vim.
This is one of those 'nothing' shell functions ...which I use all the time. If the command contains spaces, it must be quoted, e.g. $ vimcmd 'svn diff' /tmp/svndiff.out If I want to keep the output of the command that I'm running, I use vimcmd. If I don't need to keep the output, I use this: $ vim

Find Duplicate Files (based on size first, then MD5 hash)
Finds duplicates based on MD5 sum. Compares only files with the same size. Performance improvements on: $find -not -empty -type f -printf "%s\n" | sort -rn | uniq -d | xargs -I{} -n1 find -type f -size {}c -print0 | xargs -0 md5sum | sort | uniq -w32 --all-repeated=separate The new version takes around 3 seconds where the old version took around 17 minutes. The bottle neck in the old command was the second find. It searches for the files with the specified file size. The new version keeps the file path and size from the beginning.

Crash bash, in case you ever want to for whatever reason
This is a very hackish way to do it that I'm mainly just posting for fun, and I guess technically can more accurately be said to result in undefined behavior. What the command does is tell the shell to treat libpng like it's a shell plugin (which it's most certainly not) and attempt to install a "png_create_read" command from the library. It looks for the struct with the information about the command; since it's always the command name followed by "_struct", it'll look for a symbol called "png_create_read_struct". And it finds it, since this is the name of one of libpng's functions. But bash has no way to tell it's a function instead of a struct, so it goes ahead and parses the function's code as if it was command metadata. Inevitably, bash will attempt to dereference an invalid pointer or whatever, resulting in a segfault.

list files recursively by size

List all commands present on system
List all commands present on system by folder. $PATH contains all command folder separated by ':'. With ${PATH//:/ }, we change ':' in space and create a list of folder for ls command.

Create a DOS floppy image
mount with: mount -t msdos -o loop ./floppy.img /tmp/mnt

Get all documents (doc,docx,xls,xlsx,pdf,ppt,pptx,...) linked in a webpage

recurisvely md5 all files in a tree
Found this little gem here: http://info.michael-simons.eu/2008/10/25/recursively-md5sum-all-files-in-a-directory-tree/

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