How do I execute any command editing its file (

Question

I have a file temp.txt, that I want to sort with the sort command in bash.

I want the sorted results to replace the original file.

This doesn't work for example (I get an empty file):

sortx temp.txt > temp.txt

Can this be done in one line without resorting to copying to temporary files?

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EDIT: The -o option is very cool for sort. I used sort in my question as an example. I run into the same problem with other commands:

uniq temp.txt > temp.txt.

Is there a better general solution?

Answer 1

Many have mentioned the -o option. Here is the man page part.

From the man page:

   -o output-file
          Write output to output-file instead of to the  standard  output.
          If  output-file  is  one of the input files, sort copies it to a
          temporary file before sorting and writing the output to  output-
          file.

Answer 2

Read up on the non-interactive editor, ex.

Answer 3

Use the argument --output= or -o

Just tried on FreeBSD:

sort temp.txt -otemp.txt

Answer 4

Another solution:

uniq file 1<> file

Answer 5

If you insist on using the sort program, you have to use a intermediate file -- I don't think sort has an option for sorting in memory. Any other trick with stdin/stdout will fail unless you can guarantee that the buffer size for sort's stdin is big enough to fit the entire file.

Edit: shame on me. sort temp.txt -o temp.txt works excellent.

Answer 6

sort temp.txt -o temp.txt