You can use the “noclobber“ shell variable to avoid accidentally overwriting an existing file. It’s a good idea to include this variable in your shell startup file, such as the .cshrc file, as shown here:
Tips to avoid file Overwriting
in Unix
$set noclobber
The noclobber command is very handy when you’re redirecting output to a file.
Different uses:
$ echo “Hello, world” >file.txt
$ echo “This will overwrite the first greeting.” >file.txt
$ set -o noclobber
$ echo “Can we overwrite it again?” >file.txt
-bash: file.txt: cannot overwrite existing file
$ echo “But we can use the >| operator to ignore the noclobber.” >|file.txt
$ # Successfully overwrote the contents of file.txt using the >| operator
$ set +o noclobber # Changes setting back
$ echo “This will overwrite the first greeting.” >file.txt
$ set -o noclobber
$ echo “Can we overwrite it again?” >file.txt
-bash: file.txt: cannot overwrite existing file
$ echo “But we can use the >| operator to ignore the noclobber.” >|file.txt
$ # Successfully overwrote the contents of file.txt using the >| operator
$ set +o noclobber # Changes setting back
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