Carriage return for reprinting on the same line

while true; do echo -ne "$(date)\r"; sleep 1; done
The above code is just an example of printing on the same line, hit Ctrl + C to stop When using echo -ne "something\r", echo will: - print "something" - dont print a new line (-n) - interpret \r as carriage return, going back to the start of the line (-e) Remember to print some white spaces after the output if your command will print lines of different sizes, mainly if one line will be smaller than the previous Edit from reading comments: You can achieve the same effect using printf (more standardized than echo): while true; do printf "%-80s\r" "$(date)"; sleep 1; done

12
By: polaco
2009-11-17 22:45:37

What Others Think

Using terminfo here is better, IMO. Just using '\r' will not clear out junk characters on the end left by previous iterations of the loop. el1=$(tput el1); while true; do echo -ne "${el1}\r$(ps -eo %cpu,comm --sort %cpu|tail -1)"; sleep 1; done
arcege · 468 weeks and 5 days ago
Note that there are various implementations of the echo command, and not all of them support backslash codes. Also, many shells have a builtin echo command that behaves differently from /bin/echo. Therefore it is better to use printf which is standardized, so echo -ne $(date) becomes printf "%s\r" $(date) You can also easily get rid of the junk character problem that arcege mentioned: printf "%-79\r" $(date) Explanation: The "-" modifier will print the argument left-justified and overwrite the rest of the line with spaces. This assumes at least 80 characters per line, which should be more sufficient because the output from the date command is much shorter.
inof · 468 weeks and 4 days ago
That should be: printf "%s\r" "$(date)"
cfajohnson · 468 weeks and 2 days ago
Thanks for the additions guys, i edited the command
polaco · 468 weeks ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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