bash script overwrite current line completely

Question

I have been playing with a script to test the speed of various VoIP servers by pinging, I then found a progress bar script and incorporated that... because cool! now I'm trying to display the current server being tested below the status bar, I have the line overwriting but if the next server name is shorter it does not overwrite completely. I have tried various suggestions I've found but non work or they screw up my progress bar.

Im running osx but may also use this on various linux distros.

any suggestions would be great!

#!/bin/bash


HOSTS=("atlanta.voip.ms" "atlanta2.voip.ms" "chicago.voip.ms" "chicago2.voip.ms" "chicago3.voip.ms" "chicago4.voip.ms" "dallas.voip.ms" "denver.voip.ms" "denver2.voip.ms" "houston.voip.ms" "houstonnew1.voip.ms" "houstonnew2.voip.ms" "losangeles.voip.ms" "losangeles2.voip.ms" "newyork.voip.ms" "newyork2.voip.ms" "newyork3.voip.ms" "newyork4.voip.ms" "sanjose.voip.ms" "sanjose2.voip.ms" "seattle.voip.ms" "seattle2.voip.ms" "seattle3.voip.ms" "tampa.voip.ms" "tampanew1.voip.ms" "tampanew2.voip.ms" "washington.voip.ms" "washington2.voip.ms" "montreal.voip.ms" "montreal2.voip.ms" "montreal3.voip.ms" "montreal4.voip.ms" "toronto.voip.ms" "toronto2.voip.ms" "toronto3.voip.ms" "toronto4.voip.ms" "vancouver.voip.ms" "vancouver2.voip.ms" "amsterdam.voip.ms" "london.voip.ms" "melbourne.voip.ms" "paris.voip.ms")

Smallest="200000"
Server=""
tLen=${#HOSTS[@]}

#   Slick Progress Bar
#   Created by: Ian Brown (ijbrown@hotmail.com)
#   Please share with me your modifications
# Functions
PUT(){ echo -en "\033[${1};${2}H";}  
DRAW(){ echo -en "\033%";echo -en "\033(0";}         
WRITE(){ echo -en "\033(B";}  
HIDECURSOR(){ echo -en "\033[?25l";} 
NORM(){ echo -en "\033[?12l\033[?25h";}
function showBar {
        percDone=$(echo 'scale=2;'$1/$2*100 | bc)
        halfDone=$(echo $percDone/2 | bc) 
        barLen=$(echo ${percDone%'.00'})
        halfDone=`expr $halfDone + 6`
        tput bold
        PUT 7 28; printf "%4.4s  " $barLen%    
        PUT 5 $halfDone;  echo -e "\033[7m \033[0m" 
        tput sgr0
        }
# Start Script
clear
HIDECURSOR
echo -e ""                                           
echo -e ""                                          
DRAW                                           
echo -e "          PLEASE WAIT WHILE SCRIPT IS IN PROGRESS"
echo -e "    lqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqk"  
echo -e "    x                                                   x" 
echo -e "    mqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqj"
echo -e ""
echo -e ""
WRITE             


for (( i=0; i<${tLen}; i++ ))  
do
 
    showBar $i ${tLen}  


 serl=${HOSTS[$i]}
 seru=$(echo "$serl" | tr '[:lower:]' '[:upper:]')
 echo ""
 echo ""
 echo ""
 echo ""
 echo ""
 echo ""
 echo ""
 #this line needs to overwrite completley
 echo -ne "" '\r "              TESTING:"   $seru
 
 

 
 Current1=` ping -c 4 -q -i .2 ${HOSTS[$i]} | grep avg | awk -F'/' '{print $5 }'`

 Current=${Current1/./}

 if [ "$Current" -lt "$Smallest" ]
  then
   Server=${HOSTS[$i]}
   Smallest=$Current
  fi

done

clear
Smallestd=$(echo "$Smallest" | sed 's/...$/.&/')
echo "Fastest Server = $Server  @ $Smallestd ms"

You are probably looking for the ANSI escape `Erase to end of line: \033[K` — David C. Rankin, Apr 24 '15 at 17:11
possible duplicate of [Clear line before carriage return](http://stackoverflow.com/questions/28564787/clear-line-before-carriage-return) — Etan Reisner, Apr 24 '15 at 17:11

David C. Rankin · Accepted Answer · 2015-04-24T18:40:05.073

Here is an example of controlling clearing to end-of-line both during display of the meter, and in restoring the cursor after completion. I have reversed the loop to show the meter progressing from 100% (full) to 1% cleaning up after itself as it goes:

#!/bin/bash

## string of characters for meter (60 - good for 120 char width)
str='▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒'

tput civis                  # make cursor invisible

for i in `seq 100 -1 1`; do    # for 1 to 100, save cursor, restore, output, restore
    printf "\033[s\033[u Progress: %s %3d %% \033[u" "${str:0:$(((i+1)/2))}" "$i"
    sleep 0.1               # small delay
done

sleep 0.5

printf "\033[K"             # clear to end-of-line

tput cnorm                  # restore cursor to normal

exit 0

Note: cursor control and clearing during display of the meter is provided by the ANSI escapes for save cursor position and restore cursor position. After completion, clear to end of line is used to clean up. tput is used to control cursor visibility, but can also be used to save, restore and clear to end of line.

score 0 · Answer 2 · answered Apr 24 '15 at 17:13

You can pad your with spaces so you always write the same number of characters. That way you'll overwrite the extra characters from before with spaces. For example you could something like

echo -en "\r"; echo -n $(printf "            TESTING: %-40s" $seru)

score 0 · Answer 3 · answered Apr 24 '15 at 19:08

0

Thanks to David C. Rankin I have an easy working answer

    echo -ne "" '\r' "              TESTING:"   $seru '\033[K'

answered Apr 24 '15 at 19:08

JJD

392
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13

bash script overwrite current line completely

3 Answers3