String expansion - escaped quoted variable to value

Question

To get started, here's the script I'm running to get the offending string:

# sed finds all sourced file paths from inputted file.
#
# while reads each match output from sed to $SOURCEFILE variable.
# Each should be a file path, or a variable that represents a file path.
# Any variables found should be expanded to the full path.
#
# echo and calls are used for demonstractive purposes only 
# I intend to do something else with the path once it's expanded.

PATH_SOME_SCRIPT="/path/to/bash/script"

while read -r SOURCEFILE; do
    echo "$SOURCEFILE"
    "$SOURCEFILE"
    $SOURCEFILE
done < <(cat $PATH_SOME_SCRIPT | sed -n -e "s/^\(source\|\.\|\$include\) //p")

You may also wish to use the following to test this out as mock data:

[ /path/to/bash/script ]

#!/bin/bash
source "$HOME/bash_file"
source "$GLOBAL_VAR_SCRIPT_PATH"

echo "No cow powers here"

For the tl;dr crew, basically the while loop spits out the following on the mock data:

"$HOME/bash_file"
bash: "$HOME/bash_file": no such file or directory
bash: "$HOME/bash_file": no such file or directory
"$GLOBAL_VAR_SCRIPT_PATH"
"$GLOBAL_VAR_SCRIPT_PATH": command not found
"$GLOBAL_VAR_SCRIPT_PATH": command not found

My question is, can you get the variable to expand correctly, e.g., print "/home//bash_file" and "/expanded/variable/path"? I should also state that although eval works I do not intend to use it because of its potential insecurities.

Protip that any variable value used in cat | sed would be available globally, including to the calling script, so it's not because the script cannot call the variable value.

---

FIRST SOLUTION ATTEMPT

Using anubhava's envsubst solution:

SOMEVARIABLE="/home/nick/.some_path"
while read -r SOURCEFILE; do 
    echo "$SOURCEFILE"
    envsubst <<< "$SOURCEFILE"; 
done < <(echo -e "\"\$SOMEVARIABLE\"\n\"$HOME/.another_file\"")

This outputs the following:

"$SOMEVARIABLE"
""
"/home/nick/.another_file"
"/home/nick/.another_file"

Unfortunately, it does not expand the variable! Oh dear :(

---

SECOND SOLUTION ATTEMPT

Based upon the first attempt:

export SOMEVARIABLE="/home/nick/.some_path"
while read -r SOURCEFILE; do 
    echo "$SOURCEFILE"
    envsubst <<< "$SOURCEFILE"; 
done < <(echo -e "\"\$SOMEVARIABLE\"\n\"$HOME/.another_file\"")
unset SOMEVARIABLE

which produces the results we wanted without eval and without messing with global variables (for too long anyway), hoorah!

---

Good runner-ups were further suggested using eval (although potentially unsafe) which can be found in this answer and here (link courtesy of anubhava's extended comments).

Answer 1

My question is, can you get the variable to expand correctly, e.g., print "/home//bash_file" and "/expanded/variable/path"?

Yes you can use envsubst program, that substitutes the values of environment variables:

while read -r sourceFile; do
   envsubst <<< "$sourceFile"
done < <(sed -n "s/^\(source\|\.\|\$include\) //p" "$PATH_SOME_SCRIPT")