[issue15874] argparse cannot parse bash variable arguments in file-given arguments
New submission from Nat Hillard: When using the argparse argument fromfile_prefix_chars to obtain command line arguments from a file, it is not possible to make use of bash environment variables within this file. Ideally one would be able to `export BAR='/Users/x/Desktop/bar'`, and then give arguments such as: --foo $BAR and have this correctly expanded at read time to --foo '/Users/x/Desktop/bar'. To my knowledge, this is currently only possible if you give the arguments directly via the command line: python test.py --foo $BAR It would be great to be able to use environment variables within files as well! -- components: Library (Lib) messages: 169958 nosy: ZhuangZi, bethard priority: normal severity: normal status: open title: argparse cannot parse bash variable arguments in file-given arguments type: behavior versions: Python 2.7 ___ Python tracker <http://bugs.python.org/issue15874> ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue15874] argparse cannot parse shell variable arguments in file-given arguments
Nat Hillard added the comment: Indeed these are all valid points, and as a zsh user myself I certainly considered the alternative shell issue. That said, if it were at all possible, through a combination of os.environ / shlex, subprocess, and even `source` if necessary, to offload this interpretation to the user's shell (pass the shell a given string, receive its interpretation first before further processing), I could see a lot of benefit from this. Relatedly, I have seem similar requests for environment variable support in configparser, here: http://grokbase.com/t/python/python-list/03ckhw75xr/parsing-environment-variables-in-configparser-files This particular proposal is interesting in that it creates an intermediary between the file's environment variable syntax and the shell's own. Presumably if you standardized the presentation of environment variables within this file you could use os.environ once you had recognized it. That said, I can understand, however, if this is prohibitively costly to implement, and it may well be that this option is ill suited to the task I am putting it to. -- title: argparse cannot parse bash variable arguments in file-given arguments -> argparse cannot parse shell variable arguments in file-given arguments ___ Python tracker <http://bugs.python.org/issue15874> ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue15874] argparse cannot parse shell variable arguments in file-given arguments
Nat Hillard added the comment: Thank you, everyone. Defining a new type for this is just what I needed. No additional modifications are necessary on top of this new type. -- resolution: -> works for me status: open -> closed ___ Python tracker <http://bugs.python.org/issue15874> ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
