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Michael Moussa
Asked: 2009-10-24 06:48:47 +0800 CST

Supplying arguments to a bash script that uses "read" rather than $#

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A bash script was provided to me by a sysadmin which requires three values to be input by me. The values are read using "read" rather than read directly from the command-line.

echo "Enter value:"
read myValue
echo "Enter value 2:"
read myOtherValue

The three values I'd be entering are predictable, and I need to run this script frequently, so I would like to automate it; however, simply executing the script with the params in the command-line does not work.

./script.sh myValue myOtherValue

I can supply the first value if I echo it and then pipe it to the script, but that only works for the first param. I don't know how to pass the rest of them in this fashion.

echo "myValue" | ./script.sh

I do not have access to modify the script to just read the arguments.

Any ideas?

bash

4 Answers

  1. If the number of inputs is static you could use a here document:

    cat <<FIN | ./script.sh
value1
value2
FIN
    • 5
  2. Best Answer

    If you are truely unable to copy this script to your home folder and make modifications to suit your needs, you should look into expect. Expect can read/write stdin/stdout to a program in an automated fashion.

    This guide looks decent: http://www.ftlinuxcourse.com/FTLinuxCourse_Complete-2004/FTLinuxCourse/en/sysadm/chap5_3.html

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  3. echo -e "MyValue\nMyOtherValue" | ./script.sh
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  4. Similar to Gerald Combs' answer, you can use process substitution and redirection:

    ./script.sh < <(echo -e "myValue\nmyOtherValue")

    or

    ./script.sh < <(echo "myValue
myOtherValue")

    or

    ./script.sh < <(cat <<EOF
myValue
myOtherValue
EOF
)

    or even:

    ./script.sh < <(echo "myValue"; echo "myOtherValue")

    Where, instead of two "echoes", you might have two different commands that produce the output you need for input to the script.

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