Shell Programming and Scripting

kamaraj@kamaraj-laptop:~/Desktop/Scripts$ awk '{printf("%.2f\n",$1)}' decimal_file 
134.40
126.70
144.00
555.00
77.88

kamaraj@kamaraj-laptop:~/Desktop/Scripts$ cat decimal_file 
134.4
126.7
144
555
77.88

# while read -r l ; do echo "scale=2 ; $l*1/1"|bc ; done<infile
134.40
126.70
144.00
555.00
77.88

$
$ echo 123456.00  | sed -e :a -e 's/^\([^.]*[0-9]\)\([0-9]\{3\}\)/\1,\2/;ta'
123,456.00
$ echo 123456 | sed -e :a -e 's/^\([^.]*[0-9]\)\([0-9]\{3\}\)/\1,\2/;ta'
123,456
$ echo 123456789987654321123456789.12345 |  sed -e :a -e 's/^\([^.]*[0-9]\)\([0-9]\{3\}\)/\1,\2/;ta'
123,456,789,987,654,321,123,456,789.12345
$ echo -123456.66 |  sed -e :a -e 's/^\([^.]*[0-9]\)\([0-9]\{3\}\)/\1,\2/;ta'
-123,456.66
$

#!/bin/ksh93

while read num
do
   printf "%.2,f\n" $num
done < infile

134.4
126.7
144
555
77.88
12223
45679.55
3344

134.40
126.70
144.00
555.00
77.88
12,223.00
45,679.55
3,344.00