You can prefix the output of every line with a timestamp by piping the command to the following sed command:

$ command | sed "s/^/\[date +"%Y%m%d%H%M%S"]/"

Put an * between the number 5 and 6

$ echo '12345678901234567890'| sed -e 's/^.\{5\}/&*/' 12345*678901234567890

Put a comma between each number

$ echo "1234567890" |sed -e 's/./&,/g' -e 's/,$//' 1,2,3,4,5,6,7,8,9,0

Put comma after every 2, if not even then last number exist by itself

$ echo "1234567890" |sed -e 's/../&,/g' -e 's/,$//' 12,34,56,78,90

If you want to create a tar archive of only the files of a directory and exclude any subdirectories you can use the ls -la command and pipe the output to awk. However you need to remove the first 8 fields from the output and leave all of the remaining parts of the line in case there are spaces in the filename. One quick and dirty way of doing that is to set each of the 8 fields to a blank and then use sed to trim the leading spaces. You can optionally add quotation marks around the filename in your output too.

To count all the files by file extension recursively on the command line $ find . -type f | sed -n ’s/..*.//p’ | sort | uniq -c 40 3g2 5 AVI 13 DS_Store 28 JPG 30 MOV 133 MP4 64 THM 1 docx 18 jpg 1 json 4 m3u 89 m4a 2 m4r 156 m4v 41 mkv 112 mov 38 mp3 587 mp4 1 nfo 2 osp 30 png 1 sh 4 srt 6 svg 10 torrent 6 txt 5 webm 10 zip