| -o FILE |
write result to FILE instead of standard output
|
| -f |
fold lower case to upper case characters
|
| -r |
reverse the result of comparisons
|
| -n |
compare according to string numerical value
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| -k --key=POS1[,POS2] |
start a key at POS1, end it at POS2 (origin 1)
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| -t --field-separator=SEP |
use SEP instead of non-blank to blank transition
|