Add a period at end of paragraph - bash

Question

I need a command to add a period (full stop) to the end of a paragraph. I have tried the following command:
sed '/ +$ / s/$/ ./' $FILENAME
but it does not work!!

Answer 1

awk -v RS="" -v ORS=".\n\n" 1 file
This redefines the input record separator to be empty, so that awk reads blank-line separated paragraphs as a single record. It sets the output record separator to be a dot and 2 newlines. The actual awk program, 1 simple prints each record.
One side-effect is that any consecutive blank lines will be collapsed into a single blank line.
OK, sheesh
awk -v RS="" -v ORS="\n\n" '{sub(/\.?$/,".")} 1'
In action: (piping through cat -n just to point out the newlines)
echo -e "a.\n\nb\nc\n\n\nd" |
awk -v RS="" -v ORS="\n\n" '{sub(/\.?$/,".")} 1' |
cat -n
1 a.
2
3 b
4 c.
5
6 d.
7
There's an extra newline at the end, due to the ORS.
And, as a bonus, here's a bit of Perl that preserves the inter-paragraph spacing:
echo -e "a.\n\nb\nc\n\n\nd" | perl -0777 -pe 's/\.?(\n(\n+|$))/.$1/g' | cat -n
1 a.
2
3 b
4 c.
5
6
7 d.

Answer 2

Not very good, but it seems to work...
$ cat input
This is a paragraph with some text. Some random text that is not really important.
This is another paragraph with some text.
However this sentence is still in the same paragraph
$ tr '\n' '#' < input | sed 's/\([^.]\)##/\1.##/g' | tr '#' '\n'
This is a paragraph with some text. Some random text that is not really important.
This is another paragraph with some text.
However this sentence is still in the same paragraph.

Answer 3

Accumulate 'paragraphs' in the hold space. Keep accumulating as long as
the input line contains any non-space character(s).
When you get a blank/empty line, assume you have an accumulated paragraph. Swap the current (blank) line with the hold space. Replace the last non-space character in the pattern space (which is now the "paragraph" you were accumulating) with itself followed by a dot, unless that character is a dot. Print the result.
I think this does it:
$ cat test
this is a test line. one-line para
this is a test line. one-line para. with period.
this is a
two line para-
graph with dot.
this is a
two-line paragraph
with no dot
also works on last
line of file
$ sed -n \
-e '/^[[:space:]]*$/{x;s/\([^.[:space:]][[:space:]]*\)$/\1./;p;n;}' \
-e '/^[[:space:]]*[^[:space:]]/H' \
test
this is a test line. one-line para.
this is a test line. one-line para. with period.
this is a
two line para-
graph with dot.
this is a
two-line paragraph
with no dot.

Answer 4

Using sed.
sed ':loop;$!{N;b loop};s/[^\.]$/&./;s/\([^\.]\)\(\n[ \t]*\n\)/\1.\2/g' file
explanation
:loop;$!{N;b loop} will save all the lines in pattern space delimited by newline.
s/[^.]$/&./ will add . if last paragraph doesn't have dot in end.
s/\([^\.]\)\(\n[ \t]*\n\)/\1.\2/g will add dot before \n \n, which is identify as new paragraph.

Answer 5

This should work:
sed "s/[[:alpha:]]\+[^\.]$/\./" $FILENAME

Answer 6

A pure sed solution using the hold space to save all lines from a paragraph and append a period just before printing:
sed -ne '
## Append current line to "hold space".
H
## When found an empty line, get content of "hold space", remove leading
## newline added by "H" command, append a period at the end and print.
## Also, clean "hold space" to save following paragraph.
/^$/ { g; s/^\n//; s/\(.*\)\(\n\)/\1.\2/; p; s/^.*$//; h; b }
## Last line is a bit special, it has no following blank line but it is also
## an end of paragraph. It is similar to previous case but simpler.
$ { x; s/^\n//; s/$/./; p }
' infile
Assuming an infile with content:
one
two
three
four
five
six
It yields:
one
two.
three.
four
five
six.