Can i print again and again in same line?

[sky_knight02]

Can any one tell me how to print in same line again and again in shell scripting
example:
echo "-"
-------------------------
so that i can draw a line like the above, i know to print like echo "--------------" but i want to do it in loop like

while [ a -le b]
do
echo "-"
done

This command printing in next line after one loop but i want to print in same line can any one help?

and also i saw while booting some live cd during the booting process "/" "-" "\" were used and made a circular motion when process is going on.. can any one tell how to do that by shell scripting

[danielsmw]

Use echo's -n flag to not print the trailing newline. Check the echo man page.

Make sure you remember to just put a final echo with no arguments after the loop so you don't get _everything_ on the same line.

As for the rotating line... I think you need to use curses to do this, so it wouldn't be easily done in a simple bash script. That's not to say it can't be done, I just don't know how without a bit of research.

[drl]

Hi.

Here is some spinner code that runs until the process ID seen as the argument to the function does not exist. As provided, it runs until the sleep 10 terminates:

#!/bin/bash

# ^H is \b (for echo, others), 010 (octal), 08 (hex)

spinner(){
PROC=$1
while [ -d /proc/$PROC ];do
echo -ne '/\b' ; sleep 0.05
echo -ne '-\010' ; sleep 0.05
echo -n '' ; sleep 0.05
echo -n '' ; sleep 0.05
done
return 0
}

# du /usr >/dev/null 2>&1 &
sleep 10 &
# spinner $(pidof du)
# spinner $(pidof sleep)
spinner $!

Figuring this out will be good practice for you ... cheers, drl

[wje_lf]

drl's code is excellent, though I do question these lines:

echo -n '' ; sleep 0.05
echo -n '' ; sleep 0.05

Here's basically the same approach to your original question, but using syntax that may (or may not!) be more intelligible. It also demonstrates an additional feature or two which may be of interest.

#!/bin/bash

while true
do
  dasher=-$dasher
  echo -n -e '\r'$dasher/
  sleep 1
  echo -n -e '\b-'
  sleep 1
  echo -n -e '\b\\'
  sleep 1
  echo -n -e '\b|'
  sleep 1
done

The echo command is normally not executed by the echo program, so the man page would not be quite the authority here; usually it's executed as a bash internal command, so to get help on it, do this at the command line:

help echo

Hope this, um, helps.

[drl]

Hi, Bill.

It's not my code, just something I salted away when I ran across it someplace.

I'm always happy to see improvements ... cheers, drl

[sky_knight02]

Sure this helped me a lot... i learned much from you guys today... thanks guys.. but i cant understand one thing.. why we are using sleep here? i know its for slowing the process down but is there any other reason for that?


Thaks for all....

[wje_lf]

why we are using sleep here?

Just for demonstration. Without the sleep, the action would happen too fast for the demo scripts to be useful as teaching tools.

In real life you wouldn't use the sleep, unless it served some other purpose for you.

[sky_knight02]

Thanks... and those two exampls worked like a cake....

[sky_knight02]

#!/bin/bash

fwd ()
{
a=0
while [ $a -le 20 ]
do
d=-$d
echo -ne "\r$d"
sleep 0.05
echo -ne "\b-"
sleep 0.05
echo -ne "\b\\"
sleep 0.05
echo -ne "\b|"
sleep 0.05
echo -ne "\b/"
a=$(( $a + 1 ))
done
echo -ne " "
}
rev()
{
while [ 1 -le $a ]
do
echo -ne "\b"
sleep 0.05
echo -ne "\b-"
sleep 0.05
echo -ne "\b/"
sleep 0.05
echo -ne "\b|"
sleep 0.05
echo -ne "\b\\"
sleep 0.05
echo -ne "\b "
a=$(( $a - 1 ))
done
echo -ne "\r"
}

fwd
rev


#Guys this is the simple thing i done from your help..... Thanks....