I need to parse all commands in bash script and store them in list variables. After parsing completed, then execute each list variables one by one.

But I found the following error.

Here is the test script for explaining this problem:

#!/bin/sh

mkdir -p /tmp/test
echo "hello" > /tmp/test/t.txt

run_directly() {
    cd /tmp/test; echo "$(cat t.txt)"
}

run_in_time() {
    
    # set cd and run
    
    local -a cd_list=()
    
    cd_list[0]="cd"
    cd_list[1]="/tmp/test"
    
    "${cd_list[@]}"
    
    # set echo and run
    
    local -a echo_list=()
    echo_list[0]="echo"
    echo_list[1]="$(cat t.txt)"
    
    "${echo_list[@]}"
}

parse_before_run() {

    # parse all commands from elsewhere
    
    local -a cd_list=()
    
    cd_list[0]="cd"
    cd_list[1]="/tmp/test"
    
    local -a echo_list=()
    echo_list[0]="echo"
    echo_list[1]="$(cat t.txt)"
    
    # run cd
    
    "${cd_list[@]}"
    
    # run echo
    
    "${echo_list[@]}"
}

echo "---------------run_directly-----------"
cd /tmp
run_directly

echo "---------------run_in_time-----------"
cd /tmp
run_in_time

echo "---------------parse_before_run-----------"
cd /tmp
parse_before_run

Here is the output:

---------------run_directly-----------
hello
---------------run_in_time-----------
hello
---------------parse_before_run-----------
cat: t.txt: No such file or directory

Here is the expected output:

---------------parse_before_run-----------
hello

The difference between “run_in_time” and “parse_before_run” is: The run_in_time run the echo after cd to that directory while parse_before_run parse that command before that directory is being created.

How to write the echo_list[1]="$(cat t.txt)" in parse_before_run?