Programming Forums > Script Programming > Bash / Shell Scripting

jmsilver · Feb 28th, 2005, 12:50 PM

I have a simple script which reads lines from a file (using a while-read loop) and asks the user whether to perform an action on each entry. The problem is that when I use read to prompt the user input, the user read gets data from the file read. Here is the code:

(Toggle Plain Text)

#!/bin/bash

[ -f "download.list" ] || exit 1

while read LINE
do
        URL=${LINE#*,}
        TITLE=${LINE%,*}
        echo "Download $TITLE [y/n]: "
        read RESPONSE

        if [ $RESPONSE = 'y' ]; then
               echo "curl -O $URL"
        fi

done < download.list

The $LINE, $URL & $TITLE are set correctly. What happens is that $RESPONSE is set to the next line in 'download.list' rather than prompting the user for input.

Can anyone tell me what I am doing wrong?

Thanks,

Pizentios · Mar 1st, 2005, 8:57 AM

take a look at this: http://www.tldp.org/LDP/abs/html/

your answer lies within.

jmsilver · Mar 1st, 2005, 12:19 PM

Quote:

Originally Posted by Pizentios

take a look at this: http://www.tldp.org/LDP/abs/html/

your answer lies within.

Thank you for your RTFM post, they are always so helpful. I don't know why you bothered.

I read the section on 'read' I didn't find anything relvant to what I am trying to do - read within a loop of reads - but I will go back and read the rest of the site when I have time.

mackenga · May 20th, 2005, 2:35 PM

The problem is that the redirect on the loop redirects input to anything in the loop that reads input, not just what you wanted it to. You need to rephrase this loop so that you don't need to redirect on the loop statement; do a priming read and another read within the loop, say. Or,

(Toggle Plain Text)

#!/bin/bash

[ -f "download.list" ] || exit 1

for line in `cat download.list`; do
        URL=${LINE#*,}
        TITLE=${LINE%,*}
        echo "Download $TITLE [y/n]: "
        read RESPONSE

        if [ $RESPONSE = 'y' ]; then
               echo "curl -O $URL"
        fi

done

As usual, my example code is untested; forgive me if it's a brainfart.

Feb 28th, 2005, 12:50 PM	#1
jmsilver Newbie Join Date: Feb 2005 Posts: 2 Rep Power: 0	Problem read'ing from file and user input I have a simple script which reads lines from a file (using a while-read loop) and asks the user whether to perform an action on each entry. The problem is that when I use read to prompt the user input, the user read gets data from the file read. Here is the code: (Toggle Plain Text) #!/bin/bash [ -f "download.list" ] \|\| exit 1 while read LINE do URL=${LINE#,} TITLE=${LINE%,} echo "Download $TITLE [y/n]: " read RESPONSE if [ $RESPONSE = 'y' ]; then echo "curl -O $URL" fi done < download.list #!/bin/bash [ -f "download.list" ] \|\| exit 1 while read LINE do URL=${LINE#,} TITLE=${LINE%,} echo "Download $TITLE [y/n]: " read RESPONSE if [ $RESPONSE = 'y' ]; then echo "curl -O $URL" fi done < download.list The $LINE, $URL & $TITLE are set correctly. What happens is that $RESPONSE is set to the next line in 'download.list' rather than prompting the user for input. Can anyone tell me what I am doing wrong? Thanks,

Mar 1st, 2005, 8:57 AM	#2
Pizentios Programming Guru Join Date: May 2004 Location: Brandon, Manitoba, Canada Posts: 2,023 Rep Power: 7	take a look at this: http://www.tldp.org/LDP/abs/html/ your answer lies within. __________________ Profanity is the one language that all programmers understand. Check out my Blog <---updated Nov 30 2007!

May 20th, 2005, 2:35 PM	#4
mackenga Professional Programmer Join Date: Mar 2005 Location: Glasgow, Scotland Posts: 317 Rep Power: 4	The problem is that the redirect on the loop redirects input to anything in the loop that reads input, not just what you wanted it to. You need to rephrase this loop so that you don't need to redirect on the loop statement; do a priming read and another read within the loop, say. Or, (Toggle Plain Text) #!/bin/bash [ -f "download.list" ] \|\| exit 1 for line in `cat download.list`; do URL=${LINE#,} TITLE=${LINE%,} echo "Download $TITLE [y/n]: " read RESPONSE if [ $RESPONSE = 'y' ]; then echo "curl -O $URL" fi done #!/bin/bash [ -f "download.list" ] \|\| exit 1 for line in `cat download.list`; do URL=${LINE#,} TITLE=${LINE%,} echo "Download $TITLE [y/n]: " read RESPONSE if [ $RESPONSE = 'y' ]; then echo "curl -O $URL" fi done As usual, my example code is untested; forgive me if it's a brainfart.

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Programming Forums > Script Programming > Bash / Shell Scripting

Problem read'ing from file and user input