File input in bash script from an array of strings

Question

Given an array of strings, I need to input each of these strings as a source file into a build script.

1. Declare the array (the extra space at the end of the filename is deliberate):

SOURCES=( \
"../../header1.h " \
"../../source1.cpp " \
"../../header2.h " \
"../../header3.h " \
...
"./main.cpp")

2. Convert contents of array into one string:

SOURCE_AS_STR=""
for val in "${SOURCES[@]}";
do
    SOURCE_AS_STR+=$val
done

3. Redirect string into a build script:

bash my_build_script.sh < "${SOURCE_AS_STR}"

BASH terminal response: ... No such file or directory

I've tried arrays and heredoc strings but I am getting "ambiguous redirect" error as well.

Answer 1

The backslashes (when defining SOURCES) are unnecessary, but they don't harm.

In your approach, you are telling bash to use the string stored in SOURCE_AS_A_STRING as filename and feed the content of this file into the standard input of the script.

You did not specify, how my_build_script.sh expects the input, so here are various possibilities:

• If the input is to be processed via stdin, do a

  my_build_script.sh <<<$SOURCE_AS_A_STRING

• If the input should be passed to the script as a parameter, do a

  my_build_script.sh "$SOURCE_AS_A_STRING"

• If the input should be passed to the script via the environment (say, via the environment variable BUILD_INPUT), do a

  BUILD_INPUT=$SOURCE_AS_A_STRING my_build_script.sh

Of course the question is why your scripts expects an input (in whatever way) as a single string, and not as list of file names. This smells like a badly designed script file.