How do I get the last non-empty line of a file using tail in Bash?

Question

How do I get the last non-empty line using tail under Bash shell?

For example, my_file.txt looks like this:

hello

Answer 1

You can use Awk:

awk '/./{line=$0} END{print line}' my_file.txt

This solution has the advantage of using just one tool.

Answer 2

Print the last non-empty line that does not contain only tabs and spaces like this:

tac my_file.txt | grep -m 1 '[^[:blank:]]'

Note that Grep supports POSIX character class [:blank:] even if it is not documented in its manual page until 2020-01-01.

File may contain other non-visible characters, so maybe using [:space:] may be better in some cases. All space is not covered even by that, see here.

Answer 3

How about using grep to filter out the blank lines first?

$ cat rjh
1
2
3


$ grep "." rjh | tail -1
3

Answer 4

Instead of tac you can use tail -r if available.

tail -r | grep -m 1 '.'

Answer 5

if you want to omit any whitespaces, ie, spaces/tabs at the end of the line, not just empty lines

awk 'NF{p=$0}END{print p}' file

Answer 6

If tail -r isn't available and you don't have egrep, the following works nicely:

tac $FILE | grep -m 1 '.'

As you can see, it's a combination of two of the previous answers.