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Carriage return for reprinting on the same line

Terminal - Carriage return for reprinting on the same line
while true; do echo -ne "$(date)\r"; sleep 1; done
2009-11-17 22:45:37
User: polaco
Functions: echo sleep
12
Carriage return for reprinting on the same line

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

Alternatives

There is 1 alternative - vote for the best!

Terminal - Alternatives

Know a better way?

If you can do better, submit your command here.

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
Comment by arcege 357 weeks and 4 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.

Comment by inof 357 weeks and 3 days ago

That should be:

printf "%s\r" "$(date)"
Comment by cfajohnson 357 weeks and 2 days ago

Thanks for the additions guys, i edited the command

Comment by polaco 356 weeks and 6 days ago

Your point of view

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