If I redirect output of a command to same file it reads from, its contents is erased.
sed 's/abd/def/g' a.txt > a.txt
Can anyone explain why?
If I redirect output of a command to same file it reads from, its
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If I redirect output of a command to same file it reads from, its contents is erased.
sed 's/abd/def/g' a.txt > a.txt
Can anyone explain why?
The first thing the redirection does is to open the file for writing, thus clearing any existing contents. sed then tries to read this empty file you have just created, and does nothing. The file is then closed, containing nothing.