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quickly backup or copy a file with bash
This inserts timestamp instead of .bak extension.

Find the package that installed a command

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.

Printout a list of field numbers (awk index) from a CSV file with headers as first line.
Useful to identify the field number in big CSV files with large number of fields. The index is the reference to use in processing with commands like 'cut' or 'awk' involved.

Quickly CD Out Of Directories Without 5+ Aliases
I wrote this a long time ago, wondering why this wasn't floating around somewhere out there (at least not where I could find).. this seems much more simple than multiple aliases and can cd out of directories easier.

Commandline document conversion with Libreoffice
In this example, the docx gets converted to Open Document .odt format. For other formats, you'll need to specify the correct filter (Hint: see "Comments" link below for a nice list).

Count number of files in a directory
Just want to post a Perl alternative. Does not count hidden files ('.' ones).

Quick key/value display within /proc or /sys
Within /proc and /sys there are a lot of subdirectories, which carry pseudofiles with only one value as content. Instead of cat-ing all single files (which takes quite a time) or do a "cat *" (which makes it hard to find the filename/content relation), just grep recursively for . or use "grep . /blabla/*" (star instead of -r flag). For better readability you might also want to pipe the output to "column -t -s : ".

grep expression (perl regex) to extract all ip addresses from both ip and ifconfig commands output
It uses the following GNU grep options: "-o" which shows only the matching part of the line and "-P" which allows the use of Perl regular expressions.

Rename files in batch


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