Other possible ways to do it:

1. open your file in read mode, sort the content in memory, close the file, and reopen it in write mode;

2. I usually prefer to keep a copy of the original file, just in case something goes wrong. So I rename the original file (changing the extension to .bak, for example), and then open the renamed original in read mode and write to a new file having the original name (this is basically what the -i command line option does in Perl one-liners). The renamed original file can be deleted at a later point, once it has been verified that everything went right.

In reply to Re: sort a csv file then update the same file by Laurent_R
in thread sort a csv file then update the same file by john.tm

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