using a Bash variable in place of a file as input for an executable

Question

I have an executable that is used in a way such as the following:

executable -v -i inputFile.txt -o outputFile.eps

In order to be more effi

Answer 1

You can use the construct

<(command)

to have bash create a fifo with commands output for you. So just try:

-i <(echo "$inputData")

Answer 2

Note: zsh only:

To get a filename containing the contents of ${variable}, use:

<(<<<${variable})

Note:

• <<<${variable} redirects STDIN to come from ${variable}
• <<<${variable} is equivalent to (but faster than) cat <<<${variable}

So for the OP's case:

executable -v -i <(<<<${inputData}) -o outputFile.eps

Answer 3

executable -v -i <<<"${inputData}" -o outputFile.eps

will do the trick in bash.

Answer 4

Echo is not safe to use for arbitrary input.

To correctly handle pathological cases like inputdata='\ntest' or inputdata='-e', you need

executable -v -i <(cat <<< "$inputData")

In zsh, the cat is not necessary

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Edit: even this adds a trailing newline. To output the exact variable contents byte-by-byte, you need

executable -v -i <(printf "%s" "$inputData")