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Old 12-26-2017, 05:37 AM   #1
pedropt
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Sed , remove every number from user input from variable not in sequence


Hi , i am trying to use sed to search from user input into a fixed variable and remove every number from user input no matter if it is in order or not , but it is not working .

From this next example if i write "9" or 840" then since those sequences of numbers are in main variable , then sed will find them and it will remove them .

Bu what i need is to input ex: 890 , and wait to strip all the variable and search for those numbers individually and remove them if they exist .


Code:
#!/bin/bash

#some default variable
var="2840139"

#user input
echo -n "From  $var which numbers do you want to remove? : "
read -r out

#the output expected is to sed search in (var) from user input (out) 
# and remove the all digits from the main variable even if they are 
# not in squence
output=$(echo $var | sed -r "s#$out##g")

echo ""
echo "This is the left number $output"
Does anyone knows how to achieve this ?
The problem here is that sed is looking the all the user input at once and only removes the whole sequence as it is in case it finds it , but i need sed to remove all those digits from user input from main variable .

Last edited by pedropt; 12-29-2017 at 03:11 AM.
 
Old 12-26-2017, 05:48 AM   #2
syg00
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You have had how to strip a variable answered in another thread. Can you not apply that for yourself ?.
 
Old 12-26-2017, 06:00 AM   #3
pan64
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you can specify list of chars in between [ and ] - for sed.
 
Old 12-26-2017, 06:12 AM   #4
NevemTeve
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Or you could quote the complete text of this homework of yours.
 
Old 12-26-2017, 06:26 AM   #5
pedropt
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Quote:
You have had how to strip a variable answered in another thread. Can you not apply that for yourself ?.
Yup , you are right , the situation is that the logic of this script that will work with some hardware is making my head blow with the logic that must run .

It is so many code , that i get lost on its working logic if i distract just for a second .

However , thank you for pointing that up , i managed a way to get this done .

Code:
#!/bin/bash

var="2840139"

echo -n "From  $var which numbers do you want to remove? : "
read -r out

for i in $(seq ${#out}); do
a1=$(echo "${out:$i-1:1}") 
output=$(echo $var | sed -r "s#$a1##g")
var="$output"
done

echo ""
echo "This is the left number $output"
 
Old 12-26-2017, 06:54 AM   #6
keefaz
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Or without a loop and sed
Code:
${string//substring/replacement}
    Replace all matches of $substring with $replacement.
http://tldp.org/LDP/abs/html/string-manipulation.html

Code:
output=${var//[$out]/}

Last edited by keefaz; 12-26-2017 at 06:56 AM.
 
Old 12-26-2017, 10:34 AM   #7
pan64
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the minimal modification (to the OP) would be:
Code:
...
output=$(echo $var | sed -r "s#[$out]##g")
...
 
  


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