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Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.
Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):
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Recursively find php files and replace tab characters with spaces.
"\*.php" -- replace this with the files you wish to find
"expand" -- replace tabs with spaces (use "unexpand" to replace spaces with tabs)
"-t4" -- tabs represent 4 spaces
Note: The IFS="" in the middle is to prevent 'read' from eating leading/trailing whitespace in filenames.
Select a file/folder at random.
Countdown clock - Counts down from $MIN minutes to zero.
I let the date command do the maths.
This version doesn't use seq.
Are the two strings anagrams of one another?
sed splits up the strings into one character per line
the result is sorted
cmp compares the results
Note: This is not pretty. I just wanted to see if I could do it in bash.
Note: It uses fewer characters than the perl version :-)
Take a folder full of files and split it into smaller folders containing a maximum number of files. In this case, 100 files per directory.
find creates the list of files
xargs breaks up the list into groups of 100
for each group, create a directory and copy in the files
Note: This command won't work if there is whitespace in the filenames (but then again, neither do the alternative commands :-)
Calculate pi from the infinite series 4/1 - 4/3 + 4/5 - 4/7 + ...
This expansion was formulated by Gottfried Leibniz: http://en.wikipedia.org/wiki/Leibniz_formula_for_pi
I helped rubenmoran create the sum of a sequence of numbers and he replied with a command for the sequence: 1 + 2 -3 + 4 ...
This set me thinking. Transcendental numbers!
seq provides the odd numbers 1, 3, 5
sed turns them into 4/1 4/3 4/5
paste inserts - and +
bc -l does the calculation
Note: 100 million iterations takes quite a while. 1 billion and I run out of memory.