In pdb how do you reset the list (l) command line count?

Question

From PDB

(Pdb) help l
l(ist) [first [,last]]
  List source code for the current file.
  Without arguments, list 11 lines around the current line
  or continue the previous listing.
  With one argument, list 11 lines starting at that line.
  With two arguments, list the given range;
  if the second argument is less than the first, it is a count.

The "continue the previous listing" feature is really nice, but how do you turn it off?

For those arriving here wondering how to get back to the original starting set, one work-around is `w` to get line number, than for example `l 42` to see 11 lines around line 42. — Brady Trainor, Aug 29 '15 at 03:29

score 31 · Answer 1 · answered Aug 07 '12 at 14:18

31

Late but hopefully still helpful. In pdb, make the following alias (which you can add to your .pdbrc file so it's always available):

alias ll u;;d;;l

Then whenever you type ll, pdb will list from the current position. It works by going up the stack and then down the stack, which resets 'l' to show from the current position. (This won't work if you are at the top of the stack trace.)

answered Aug 07 '12 at 14:18

Ghopper21

10,287
10
63
92

How to add it in the `pdb` config? Now I have to run it every time it breaks on `pdb.set_trace()`. – srgbnd Nov 01 '16 at 12:00
1

Put the alias line to a file `.pdbrc` in CWD or $HOME; On Windows you may also need to set HOME=%HOMEPATH% manually in the envs because pdb is not using `os.path.expanduser('~')` correctly. – kxr Apr 19 '17 at 11:21
Best answer :) Thanks. – Apteryx May 12 '17 at 23:45
1

I've realised that `ll` is actually an alias that brings you to the end of the file, so I ended up naming it `rl` which stands for "reset list". Hope this helps! – Caumons Nov 15 '17 at 12:15
1

this is useless nowadays, just do `l.` – Jules G.M. Dec 07 '21 at 01:42

plhn · Answer 2 · 2020-07-07T05:20:01.457

25

Try this.

(pdb) l .

Maybe you can always type the dot.

ps. You may consider to use pudb. This is a nice UI to pdb what gdbtui is to gdb.

edited Jul 07 '20 at 05:20

answered Sep 17 '18 at 08:05

plhn

5,017
4
47
47

2

This should have more upvotes I think...nice answer. I've been annoyed by this for a long time now, and would always type random line numbers till I could figure out where I was. Thanks! – Matt Messersmith Dec 14 '18 at 16:40

score 6 · Answer 3 · edited Feb 16 '21 at 14:44

If you use epdb instead of pdb, you can use "l" to go forward like in pdb, but then "l." goes back to the current line number, and "l-" goes backwards through the file. You can also use until # to continue until a given line. Epdb offers a bunch of other niceties too. Need to debug remotely? Try serve() instead of set_trace() and then telnet in (port 8080 is the default port).

import epdb
epdb.serve()

score 5 · Answer 4 · answered Aug 23 '09 at 15:11

5

I don't think there is a way to turn it off. It's annoyed me enough that once I went looking in the pdb source to see if there was an undocumented syntax, but I didn't find any.

There really needs to be a syntax that means, "List the lines near the current execution pointer."

answered Aug 23 '09 at 15:11

Ned Batchelder

364,293
75
561
662

1

That is both great and horrible news. It's great because now I know this is not a stupid question, horrible because I really like something like this. Since we are going into the feature request category then I'm thinking the best will be to have a reverse operation. Lets call it "rlist" that will be a reverse pager on list. So doing (Pdb) l (Pdb) r will get you to the same spot. – Jorge Vargas Aug 24 '09 at 13:49

Mike Boers · Accepted Answer · 2009-08-24T19:42:51.500

You could monkey patch it for the behavior you want. For example, here is a full script which adds a "reset_list" or "rl" command to pdb:

import pdb

def Pdb_reset_list(self, arg):
    self.lineno = None
    print >>self.stdout, "Reset list position."
pdb.Pdb.do_reset = Pdb_reset_list
pdb.Pdb.do_rl = Pdb_reset_list

a = 1
b = 2

pdb.set_trace()

print a, b

One could conceivably monkey patch the standard list command to not retain the lineno history.

edit: And here is such a patch:

import pdb
Pdb = pdb.Pdb

Pdb._do_list = Pdb.do_list
def pdb_list_wrapper(self, arg):
    if arg.strip().lower() in ('r', 'reset', 'c', 'current'):
        self.lineno = None
        arg = ''
    self._do_list(arg)
Pdb.do_list = Pdb.do_l = pdb_list_wrapper

a = 1
b = 2

pdb.set_trace()

print a, b

Thank you I guess this is the way to go for now. Perhaps a patch proposal for python itself? — Jorge Vargas, Sep 18 '09 at 05:57

In pdb how do you reset the list (l) command line count?

5 Answers5