The linecache module allows one to get any line from any file,
while attempting to optimize internally, using a cache, the common case where many lines are
read from a single file. This is used by the traceback module to retrieve source lines for inclusion
in the formatted traceback.
The linecache module defines the following functions:
- Get line lineno from file named filename. This function will never
throw an exception -- it will return
'' on errors (the terminating newline
character will be included for lines that are found).
If a file named filename is not found, the function will look for it in the
- Clear the cache. Use this function if you no longer need lines from files previously
read using getline().
- Check the cache for validity. Use this function if files in the cache may have changed
on disk, and you require the updated version.
>>> import linecache
>>> linecache.getline('/etc/passwd', 4)