How to read line by line from file, count specific character

Question

I have a data in file.txt like below

N4*1
NM1*IL*2
PER*IC*XM*

how can i read line by line and get the character * count ?

Pseudocode

#!bash/sh
cd `dirname $0`

filelinecount=echo '$(wc -l file.txt)'

if [ $filelinecount -gt 0 ] ; then

      for (int i=0, i++); do 
         fileline=$i  (STORES LINE IN VARIABLE)
         charactercount= cat '$fileline | wc [*] $fileline'
        (GET CHARACTER [*] COUNT AND STORED IN VARIABLE)
         echo $charactercount 
      done
else
   echo "file.txt don't contain any lines"
fi

Expected output: 'For' Loop should read line by line from file and store each line in variable "fileline" then count the characters [*] and store in variable "charactercount" then print the variable $charactercount. This loop has to repeat for for all the files in the file. How can i achieve this in 'for' loop ?

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This is not a duplicate question as this question clearly asked count of characters using "for" loop. "Count occurrences of a char in a string using Bash" post don't have answer to this post

Please post expected output you want to have matching the sample input you posted. — KamilCuk, Jul 31 '19 at 00:55

KamilCuk · Answer 1 · 2019-07-31T07:55:33.193

0

tr -d -c '*\n' file.txt | awk '{print length}'

Remove everything except stars and newlines from the file. Then print the line lengths.

edited Jul 31 '19 at 07:55

answered Jul 31 '19 at 00:52

KamilCuk

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Mihir Luthra · Accepted Answer · 2019-07-31T14:59:59.813

0

awk '{print gsub(/\*/,$0)}' file

To achieve the same in a loop:

#! /bin/bash

while read line
do
    grep -o '*' <<<"$line" | grep -c .
done < file

This should print * count per line.

Update as per the comment:

#! /bin/bash


while read line
do

    echo "$line" | awk -F"[*]" '{print NF-1}'
done < file

[ ! -s file ] && echo "no lines in file"

[ ! -s file ] has nothing to do with loop. -s flag checks if file has contents. If it has t returns true. But in your case you want opposite behaviour so we used !. So when file is empty, it returns true and && causes the next command to execute i.e. echo "no lines in file”.

edited Jul 31 '19 at 14:59

answered Jul 31 '19 at 01:40

Mihir Luthra

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Thank You. But i want this to achieve in for loop as posted in original post. Each line has to be stored in a variable and then take the character * count in variable then print that count. – skv Jul 31 '19 at 01:45
grep -o '*' <<<"$line" | grep -c not working – skv Jul 31 '19 at 02:33
@skv, there is a dot "." after that if you see carefully and i would like to know which os do you use? – Mihir Luthra Jul 31 '19 at 02:41
I didn't use "." anyway i got it working using echo. echo "$line" | awk -F"[*]" '{print NF-1}' – skv Jul 31 '19 at 02:43
how do i echo if there are no lines then echo "no lines in a file" ? – skv Jul 31 '19 at 03:06
@skv, check the updated answer. – Mihir Luthra Jul 31 '19 at 03:11
works perfectly, but i want to understand how it works. it is given outside of while loop, so does it work in sequence order and not related to while loop ? – skv Jul 31 '19 at 14:02
@skv, see the updated answer. – Mihir Luthra Jul 31 '19 at 15:00
Thanks for the explantion @Mihir – skv Jul 31 '19 at 15:02
@skv, Kindly give a read to https://stackoverflow.com/help/someone-answers – Mihir Luthra Aug 02 '19 at 14:05

How to read line by line from file, count specific character

2 Answers2