How to resize progress bar according to available space?

I am looking to get an effect where the length of my progress bar resizes accordingly to my PuTTY window. This effect is accomplished with wget's progress bar.

Here is my program I use in my bash scripts to create a progress bar:

_progress_bar

#!/bin/bash

maxwidth=50     # line length (in characters)
filled_char="#"
blank_char="."

current=0 max=0 i=0

current=${1:-0} 
max=${2:-100} 

if (( $current > $max )) 
then 
    echo >&2 "current value must be smaller max. value" 
    exit 1 
fi
percent=`awk 'BEGIN{printf("%5.2f", '$current' / '$max' * 100)}'`

chars=($current*$maxwidth)/$max
echo -ne " ["

while (( $i < $maxwidth )) 
do 
    if (( $i <= $chars ));then
        echo -ne $filled_char 
    else
        echo -ne $blank_char
    fi 
    i=($i+1)
done 

echo -ne "] $percent%\r" 


if (( $current == $max )); then
    echo -ne "\r"
    echo
fi

Here is an example of how I use it, this example finds all Tor Onion proxies Exit nodes and bans the IP under a custom chain:

#!/bin/bash


IPTABLES_TARGET="DROP"
IPTABLES_CHAINNAME="TOR"

WORKING_DIR="/tmp/"

# get IP address of eth0 network interface
IP_ADDRESS=$(ifconfig eth0 | awk '/inet addr/ {split ($2,A,":"); print A[2]}')



if ! iptables -L "$IPTABLES_CHAINNAME" -n >/dev/null 2>&1 ; then            #If chain doesn't exist
    iptables -N "$IPTABLES_CHAINNAME" >/dev/null 2>&开发者_开发技巧amp;1               #Create it
fi


cd $WORKING_DIR


wget -q -O - http://proxy.org/tor_blacklist.txt -U NoSuchBrowser/1.0 > temp_tor_list1
sed -i 's|RewriteCond %{REMOTE_ADDR} \^||g' temp_tor_list1
sed -i 's|\$.*$||g' temp_tor_list1
sed -i 's|\\||g' temp_tor_list1
sed -i 's|Rewrite.*$||g' temp_tor_list1

wget -q -O - "https://check.torproject.org/cgi-bin/TorBulkExitList.py?ip=$IP_ADDRESS&port=80" -U NoSuchBrowser/1.0 > temp_tor_list2
wget -q -O - "https://check.torproject.org/cgi-bin/TorBulkExitList.py?ip=$IP_ADDRESS&port=9998" -U NoSuchBrowser/1.0 >> temp_tor_list2
sed -i 's|^#.*$||g' temp_tor_list2



iptables -F "$IPTABLES_CHAINNAME"


CMD=$(cat temp_tor_list1 temp_tor_list2 | uniq | sort)
UBOUND=$(echo "$CMD" | grep -cve '^\s*$')

for IP in $CMD; do
    let COUNT=COUNT+1
    _progress_bar $COUNT $UBOUND
    iptables -A "$IPTABLES_CHAINNAME" -s $IP -j $IPTABLES_TARGET
done

iptables -A "$IPTABLES_CHAINNAME" -j RETURN


rm temp_tor*

Edit:

I realized that first example people may not want to use so here is a more simple concept:

#!/bin/bash

for i in {1..100}; do
    _progress_bar $i 100
done

I made a few changes to your script:

• Converted it to a function. If you want to keep it in a separate file so it's available to multiple scripts, just source the file in each of your scripts. Doing this eliminates the overhead of repeatedly calling an external script.
• Eliminated the while loop (which should have been a for ((i=0; $i < $maxwidth; i++)) loop anyway) for a drastic speed-up.
• Changed your arithmetic expressions so they evaluate immediately instead of setting them to strings for later evaluation.
• Removed dollar signs from variable names where they appear in arithmetic contexts.
• Changed echo -en to printf.
• Made a few other changes
• Changed the AWK output so "100.00%" is decimal aligned with smaller values.
• Changed the AWK command to use variable passing instead of "inside-out: quoting.

Here is the result:

_progress_bar () {
    local maxwidth=50     # line length (in characters)
    local filled_char="#"
    local blank_char="."

    local current=0 max=0 i=0
    local complete remain

    current=${1:-0}
    max=${2:-100}

    if (( current > max ))
    then
        echo >&2 "current value must be smaller than max. value"
        return 1
    fi
    percent=$(awk -v "c=$current" -v "m=$max" 'BEGIN{printf("%6.2f", c / m * 100)}')

    (( chars = current * maxwidth / max))

    # sprintf n zeros into the var named as the arg to -v
    printf -v complete '%0*.*d' '' "$chars" ''
    printf -v remain '%0*.*d' '' "$((maxwidth - chars))" ''

    # replace the zeros with the desired char
    complete=${complete//0/"$filled_char"}
    remain=${remain//0/"$blank_char"}

    printf ' [%s%s] %s%%\r' "$complete" "$remain" "$percent"
}

What was the question? Oh, see BashFAQ/091. Use tput or bash -i and $COLUMNS. If you use bash -i, however, be aware that it will have the overhead of processing your startup files

After some google searching I did find the following:

tput cols will return the amount of columns, much like Sdaz's suggested COLUMNS var.

Therefore I am going with: maxwidth=$(tput cols) unless someone else has a more bulletproof way without requiring tput

Bash exports the LINES and COLUMNS envvars to the window rows and column counts, respectively. Furthermore, when you resize the putty window, via the SSH or telnet protocols, there is sufficient logic in the protocol to send a WINCH signal to the active shell, which then resets these values to the new window dimensions.

In your bash script, use the COLUMNS variable to set the current dimensions, and divide 100 / progbarlen (progbarlen based on a portion of the COLUMNS variable) to get how many percentage points make up one character, and advance them as your progress moves along. To handle the resizing dynamically, add a handler for SIGWINCH (via trap) and have it reread the COLUMNS envvar, and redraw the progress bar using the new dimensions.

(I haven't tested this in a shell script, and there may be some additional logic required, but this is how bash detects/handles resizing.)