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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.
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This command produces no output, but its exit status is 0 ("true") if $file is text, non-0 ("false") if $file is binary (or is not accessible).
-q suppresses all the output of grep
-I is the trick: if a binary file is found, it is considered a non-match
-m 1: limit "output" to first match (speed up for big files)
.: the match string, "." stands for any character
Usage: e.g. run editor only on text files
grep -qIm 1 . $file && vi $file