To remove the last newline character from a file in Linux, even if the last line is not empty, you can use one of these methods:

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1. Using sed

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sed -i -e '${/^$/d;}' -e ':a;/^\n*$/{$d;N;ba;}' file.txt

• This removes the last newline, even if the last line is not empty.

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2. Using tr (for a single trailing newline)

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tr -d '\n' < file.txt > temp && mv temp file.txt

• This removes all newlines, so it's only suitable if you want to remove the last one and the file has no other newlines.

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3. Using awk

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awk 'NR>1{printf "%s", prev} {prev=$0} END{printf "%s", prev}' file.txt > temp && mv temp file.txt

• This prints all lines without adding a newline at the end.

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4. Using head (if the file has at least one line)

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head -c -1 file.txt > temp && mv temp file.txt

• This removes the last character (which is a newline if the file ends with one).

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5. Using perl

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perl -pi -e 'chomp if eof' file.txt

• This removes the last newline if it exists.

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Which one should you use?

• For most cases, sed or perl are the most reliable.
• If you want to remove only the last newline and keep the rest of the file intact, use sed or perl.