Quit Less with Pexpect

Question

I have 3 files, a.py, b.sh, and text.txt. Their contents follow:

a.py:

#!/usr/bin/env python
import os, pexpect

class zz:
    def __init__(self):
        child = pexpect.spawn ('/home/usr/Desktop/b.sh')

        ###  VVV     LINE IN QUESTION BELOW    VVV
        child.expect(pexpect.EOF)

        child.sendline('q')
        child.interact()

z = zz()

b.sh:

less /home/usr/Desktop/text.txt
echo 'all done'
sleep 3

text.txt:

thisistext

Files text.txt and b.sh are read-only and must not be changed. How does one quit less using pexpect from within a.py?

Answer 1

Assuming you don't want to do anything with the data, just read the first screen of data from less and then issue the 'q'.

(EDIT: This needed a tweak to give 'read' a size so that it didn't wait for the default size or eof)

#!/usr/bin/env python
import os, pexpect

class zz:
    def __init__(self):
        child = pexpect.spawn ('/home/usr/Desktop/b.sh')
        # grab the first screen from 'less'
        child.read(1)
        child.send('q')

z = zz()

Here is the code I used for test:

~/tmp/reader$ cat a.py
#!/usr/bin/env python
import pexpect

try:
    open('status.txt', 'w')
    child = pexpect.spawn('/bin/sh "./b.sh"', timeout=10)
    child.send('q')
    child.expect(pexpect.EOF)
except Exception,e:
    print 'exception'
print open('status.txt').read()


~/tmp/reader$ cat text.txt
iamtext

~/tmp/reader$ cat b.sh
#!/bin/sh
less text.txt
echo 'all done'
sleep 3
date > status.txt