Bash readline not working inside a while loop

Question

I have tried with this one day but still i cant figure out why? echo is working fine but if is always return false.

#!/bin/sh -e
   scan_fileExists(){
        while read file; do
            echo $file #echo is working
            if [ -f $file ]; then
                echo "Yes"
            fi
        done < $1
   }
   scan_fileExists "/home/myfile"

I guess your problem is that "Yes" is not getting printed at all? What are the 3 text lines in /home/myfile? are they filenames? — Arjun Mathew Dan
– Arjun Mathew Dan, Commented Mar 24, 2015 at 5:26
if [ -f "$file" ]; then ... (Note the quotes..) Also, are you sure these files exist? — anishsane
– anishsane, Commented Mar 24, 2015 at 5:33
Yes AMD you're correct, its not getting printed at all rather than i hard code the file path instead of use $file; yes /home/myfile inclusing file names — Dhanan
– Dhanan, Commented Mar 24, 2015 at 5:34
I have tried both with and without quotes,yes files are exists; — Dhanan
– Dhanan, Commented Mar 24, 2015 at 5:36

Cyrus · Accepted Answer · 2015-03-24 06:19:11Z

1

Try this:

#!/bin/bash -e                               # modified
   scan_fileExists(){
        x=$'\r'                              # added
        while read file; do
            echo $file #echo is working
            if [ -f ${file%${x}*} ]; then    # modified
                echo "Yes"
            fi
        done < $1
   }
   scan_fileExists "/home/myfile"

Other method to keep sh as shell (disadvantage: while runs as member of a pipe in a subshell):

#!/bin/sh -e
   scan_fileExists(){
        tr -d "\r" < $1 | while read file; do  # modified
            echo $file #echo is working
            if [ -f $file ]; then
                echo "Yes"
            fi
        done                                   # modified
   }
   scan_fileExists "/home/myfile"

edited Mar 24, 2015 at 6:19

answered Mar 24, 2015 at 5:59

Cyrus

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2 Comments

Dhanan Over a year ago

Yes its working perfectly, could you please describe whats the wrong with my snippet and what is the logic behind your script any way superb and thank you very much

Cyrus Over a year ago

Your /home/myfile contains at end of each line an additional disturbing carriage return (hex 0d). Unix/Linux uses only a newline (hex 0a) to mark end of line, Windows uses newline and carriage return.

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