tailhead

Python tail is a simple implementation of GNU tail and head.

It provides 3 main functions that can be performed on any file-like object that supports seek() and tell().

• tail - read lines from the end of a file
• head - read lines from the top of a file
• follow - read lines as a file grows

It also comes with pytail, a command line version offering the same functionality as GNU tail. This can be particularly useful on Windows systems that have no tail equivalent.

• tailhead on GitHub
• tailhead on Pypi

Installation

Install with pip or easy_install.

pip install tailhead

Examples

import tailhead
f = open('test.txt', 'w')
for i in range(11):
    f.write('Line %d\\n' % (i + 1))
f.close()

Tail

# Get the last 3 lines of the file
tailhead.tail(open('test.txt', 'rb'), 3)
# [b'Line 9', b'Line 10', b'Line 11']

Head

# Get the first 3 lines of the file
tailhead.head(open('test.txt', 'rb'), 3)
# [b'Line 1', b'Line 2', b'Line 3']

# Get all lines but last 6 lines of the file
tailhead.head(open('test.txt', 'rb'), -6)
# [b'Line 1', b'Line 2', b'Line 3', b'Line 4', b'Line 5']

Follow

# Follow the file as it grows and handle file rotation if it occurs
import time
for line in tailhead.follow_path('test.txt'):
    if line is not None:
        print(line)
    else:
        time.sleep(1)

Running Tests

Tailer currently only has doctests.

Run tests with nose:

nosetests --with-doctest tailhead

Run tests with doctest:

python -m doctest -v tailhead/__init__.py