Interactive command in command substitution bash script

Question

I'm writing a shell script that asks for a value and depending on the valued entered returns a value. Imagine that it's called "reve" and contains something like

read fname
rev << EOF 
$fname
EOF

Then if I have a file that is called "file.txt" and I do

vi `./reve`

Then waits for user input. If I type "txt.elif" vi opens "file.txt". Correct until now. But the problem is when the script is something like the following

echo "Enter inverted file name"
read fname
rev << EOF 
$fname
EOF

Then it tries to open a file called "Enter inverted file name".

Is it possible to ask for the value with the text and after that use the returned value only?

Thanks in advance.

Thiago Curvelo · Accepted Answer · 2011-10-20 21:32:45Z

3

If you really need it to be interactive, then you could print the message on stderr instead.

echo "Enter inverted file name" > /dev/stderr
read fname
rev << EOF 
$fname
EOF

answered Oct 20, 2011 at 21:32

Thiago Curvelo

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Comments

Gordon Davisson · Accepted Answer · 2011-10-21 00:34:16Z

1

Unless you're using a really old shell, read should have a -p option to supply a prompt. It automatically sends the prompt to stderr instead of stdout, and skips the linefeed (so the response is on the same line as the prompt):

read -p "Enter inverted file name: " fname
rev << EOF 
$fname
EOF

answered Oct 21, 2011 at 0:34

Gordon Davisson

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Comments

Simon C · Accepted Answer · 2011-10-21 13:38:30Z

1

Force writing to, and reading from, the terminal using /dev/tty.

In your example this will be:

echo -e "Enter inverted file name: \c" > /dev/tty
read fname < /dev/tty
rev << EOF 
$fname
EOF

I used echo -e ... \c so no newline is printed and your input is entered on the same line.

answered Oct 21, 2011 at 13:38

Simon C

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