从bash脚本重定向时，将变量与字符串python比较不起作用

Question

First I'll show you both the bash and python script (both are in the /bin directory on my mac):

The bash script ( esh_1 ):

#! /bin/bash

echo -n "Enter bash or natural-language command: "
read INPUT
echo $INPUT > ~/USER_INPUT.txt
$INPUT
if (( $? )); then echo Redirected to Python Script; esh_2; cat ~/USER_INPUT.txt; else echo Did not redirect to Python Script;  fi
esh_1

The python script ( esh_2 ):

#! /usr/bin/python2.7

with open('/Users/bendowling/USER_INPUT.txt', 'r') as UserInputFile:
    UserInput = UserInputFile.read()

UserInputFile = open('/Users/bendowling/USER_INPUT.txt', 'w+')

if UserInput == 'List contents':
    UserInputFile.write("ls")
else:
    print "Didn't work"

UserInputFile.close()

The bash script takes the user's input, stores it in a temporary file called USER_INPUT.txt , and checks if it runs correctly. If it doesn't, it calls esh_2 (the python script) which reads the USER_INPUT.txt file, taking the user's input. It then checks if it's equal to the string "List contents" . If it is, then it writes "ls" to the text file. It then closes the file. The bash file then cats the command stored in the text file (in the future I will make it run it as a command). The script then starts again.

The problem is that when I enter "List contents" into the shell, it doesn't work, thus printing "Didn't work" . However, if I go into the text file myself and write "List contents" , the python script works and writes "ls" to the text file. I have no clue why this is happening. I would gladly appreciate any help on this matter.

Thanks, b3n

Answer 1

When you read() the file, you may get a newline character '\\n' in your string. Try either

if UserInput.strip() == 'List contents':

or

if 'List contents' in UserInput:

Also note that your second file open could also use with :

with open('/Users/.../USER_INPUT.txt', 'w+') as UserInputFile:
    if UserInput.strip() == 'List contents': # or if s in f:
        UserInputFile.write("ls")
    else:
        print "Didn't work"