问题
I've used 'uniq -d -c file' in many shell scripts on linux machines, and it works. On my MAC (OS X 10.6.7 with developer tools installed) it doesn't seems to work:
$ uniq -d -c testfile.txt
usage: uniq [-c | -d | -u] [-i] [-f fields] [-s chars] [input [output]]
It would be nice if anyone could checks this.
回答1:
Well, it's right there in the Usage message. [ -c | -d | -u] means you can use one of those possibilities, not two.
Since OSX is based on BSD, you can check that here or, thanks to Ignacio, the more Apple-specific one here.
If you want to achieve a similar output, you could use:
do_your_thing | uniq -c | grep -v '^ *1 '
which will strip out all those coalesced lines that have a count of one.
回答2:
You can try this awk solution
awk '{a[$0]++}END{for(i in a)if(a[i]>1){ print i ,a[i] } }' file
来源：https://stackoverflow.com/questions/5699339/strange-behavior-of-uniq-on-darwin-shells