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Function to check whether a regular file ends with a newline

Terminal - Function to check whether a regular file ends with a newline
endnl () { [[ -f "$1" && -s "$1" && -z $(tail -c 1 "$1") ]]; }
2010-08-25 12:06:10
User: quintic
Functions: tail
Function to check whether a regular file ends with a newline

tail -c 1 "$1" returns the last byte in the file.

Command substitution deletes any trailing newlines, so if the file ended in a newline $(tail -c 1 "$1") is now empty, and the -z test succeeds.

However, $a will also be empty for an empty file, so we add -s "$1" to check that the file has a size greater than zero.

Finally, -f "$1" checks that the file is a regular file -- not a directory or a socket, etc.


There is 1 alternative - vote for the best!

Terminal - Alternatives
end_w_nl() { [[ $(tail -c1 $1 | xxd -ps) == 0a ]] }
2012-09-18 20:11:29
User: xro
Functions: tail
Tags: tail xxd zsh
end_w_nl filename

will check if the last byte of filename is a unix newline character. tail -c1 yields the file's last byte and xxd converts it to hex format.

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