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Shell script accepting input from a pipe AND the keyboard

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Join Date: Mar 2008

Posts: 2

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Robert72

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Shell script accepting input from a pipe AND the keyboard

Oct 8th, 2008

I'd like to write a shell script that'd parse data from a pipe and then ask the user questions.
ie:

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 Shell Scripting Syntax (Toggle Plain Text) 
echo "Ann Bob Charlie" | checkuser.sh
  checkuser.sh starting
    Ann is OK.
    Bob is not in the system. Add Bob? (y/n):
echo "Ann Bob Charlie" | checkuser.sh
  checkuser.sh starting
    Ann is OK.
    Bob is not in the system. Add Bob? (y/n):

I know a couple ways to read from a pipe:

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Shell Scripting Syntax (Toggle Plain Text)

names="`cat`"

and

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 Shell Scripting Syntax (Toggle Plain Text) 
names=""
while read myline; do
  names="$names\n$myline"
done
names=""
while read myline; do
  names="$names\n$myline"
done

But I don't know how to make the script start looking to he keyboard for input from the pipe's exhausted. I'd love to know exactly how the machine thinks of these kinds of things. I mean, is the terminal file (ie /dev/pts/12) still "attached" to the session? Is the logical definition of "stdin" or "file descriptor 0" changed in some way?

Many thanks for any insightful insights!