-based pc we'll see os popen in action again in where we'll deploy it to read the results of constructed command line that times code alternativesand in where it will be used to compare outputs of scripts being tested tools like os popen and os system (and the subprocess module not shown hereallow you to leverage every command-line program on your computerbut you can also write emulators with in-process code for examplesimulating the unix awk utility' ability to strip columns out of text files is almost trivial in pythonand can become reusable function in the processawk emulationextract column from whitespace-delimited file for val in [line split()[ for line in open('input txt')]print(valsamebut more explicit code that retains result col [for line in open('input txt')cols line split(col append(cols[ ]for item in col print(itemsamebut reusable function (see next part of bookdef awker(filecol)return [line rstrip(split()[col- for line in open(file)print(awker('input txt' )print(',join(awker('input txt' ))list of strings put commas between by itselfthoughpython provides file-like access to wide variety of data--including the text returned by websites and their pages identified by urlthough we'll have to defer to part for more on the package import used hereand other resources for more on such tools in general ( this works in xbut uses urllib instead of urlib requestand returns text strings)from urllib request import urlopen for line in urlopen(print(lineb'\nb'\nb'\nb"mark lutz' book support site\netc summary in this we explored python' looping statements as well as some concepts related to looping in python we looked at the while and for loop statements in depthand we learned about their associated else clauses we also studied the break and continue statementswhich have meaning only inside loopsand met several built-in summary