Useful Snippets

Some useful scripting snippets in Bash/Python.

Use Cases

Convert Bash seperated values to a literal array/list string

The example is using space separated values but the separator could be anything.

args="1 2 apple orange arg1 arg2"
sepArgs=`echo -n '['; for arg in ${args}; do case "$arg" in +([0-9]) ) echo -n "${arg}, " ;;+([-a-zA-Z0-9_]) ) echo -n "\"${arg}\", " ;; esac; done`
echo "${sepArgs:0:-2}]"

The output would be like this:

[1, 2, "apple", "orange", "arg1", "arg2"]

Now the above array/list is a BASH text value. You will need to convert that text into the appropriate data type in your PL.

Now assuming that the above snippet was put into a file called "to_list.sh", we could just execute the script from Python to get the output and evaluate it into an actual Python list, which brings us to the next use case.

Convert Bash literal array/list string into a Python list

Iterating on the previous use case, we could just simply call the Bash script from our python script like this:

try:
        output = subprocess.check_output(bashCommand)
	l = ast.literal_eval(output)
except Exception as e:
        error = str(e)

if l:
	print(l, l[0])