subst 0.3.1

`subst` is simple utility to replace one string into another in given list of files.

subst
=====

`subst` is simple utility to replace one string into another in given list of files.

Current stable version
----------------------

0.3.1

But why?
--------

1. There is `sed` for example?

Yes, it is. But `sed` use regexps engine called "Basic Regular Expressions", or "Extended
Regular Expression". PCRE is much more widely used dialect.

2. So I can use Perl!

Of course you can. But not everyone know how to use Perl. I know, but `subst` is IMHO
simpler to use.

OK, so how to use it?
---------------------

Simple
------

echo 'Hello World!' | subst -s 's/Hello/Hi/' -

or:

subst -p '(192\.168)\.1\.(10)' -r '\1.0.\2' /etc/hosts

More
----

Everything is in help :) Just execute:

subst --help

Look at result:

% subst --help
usage: subst.py [-h] [-p PATTERN] [-r REPLACE] [--eval-replace] [-t STRING]
[-s "s/PAT/REP/gixsm"] [-c COUNT] [-l] [-i]
[--pattern-dot-all] [--pattern-verbose] [--pattern-multiline]
[--utf8] [--encoding-input ENCODING_INPUT]
[--encoding-file ENCODING_FILE]
[--encoding-filesystem ENCODING_FILESYSTEM] [-b] [-e EXT]
[--stdin] [--stdout] [--verbose] [--debug] [-v]
[files [files ...]]

Replace PATTERN with REPLACE in many files.

positional arguments:
files file to parse.

optional arguments:
-h, --help show this help message and exit
-p PATTERN, --pattern PATTERN
pattern to replace for. Supersede --pattern-and-
replace. Required if --replace is specified.
-r REPLACE, --replace REPLACE
replacement. Supersede --pattern-and-replace. Required
if --pattern is specified.
--eval-replace if specified, make eval data from --replace(should be
valid Python code). Ignored with --pattern-and-replace
argument.
-t STRING, --string STRING
if specified, treats --pattern as string, not as
regular expression. Ignored with --pattern-and-replace
argument.
-s "s/PAT/REP/gixsm", --pattern-and-replace "s/PAT/REP/gixsm", --pattern-and-replace "s/PAT/REP/gixsm"
pattern and replacement in one:
s/pattern/replace/g(pattern is always regular
expression, /g is optional and stands for --count=0,
/i == --ignore-case, /s == --pattern-dot-all, /m ==
--pattern-multiline).
-c COUNT, --count COUNT
make COUNT replacements for every file (0 makes
unlimited changes, default).
-l, --linear apply pattern for every line separately. Without this
flag whole file is read into memory.
-i, --ignore-case ignore case of characters when matching
--pattern-dot-all with this flag, dot(.) character in pattern match also
new line character (see:
http://docs.python.org/2/library/re.html#re.DOTALL).
--pattern-verbose with this flag pattern can be passed as verbose(see:
http://docs.python.org/2/library/re.html#re.VERBOSE).
--pattern-multiline with this flag pattern can be passed as multiline(see:
http://docs.python.org/2/library/re.html#re.MULTILINE)
.
--utf8, -u Use UTF-8 in --encoding-input, --encoding-file and
--encoding-filesystem
--encoding-input ENCODING_INPUT
set encoding for parameters like --pattern etc
(default for your system: ascii)
--encoding-file ENCODING_FILE
set encoding for content of processed files (default
for your system: ascii)
--encoding-filesystem ENCODING_FILESYSTEM
set encoding for paths and filenames (default for your
system: utf-8)
-b, --no-backup disable creating backup of modified files.
-e EXT, --backup-extension EXT
extension for backup files(ignore if no backup is
created), without leading dot. Defaults to: "bak".
--stdin read data from STDIN(implies --stdout)
--stdout output data to STDOUT instead of change files in-
place(implies --no-backup)
--verbose show files and how many replacements was done
--debug show more informations
-v, --version show version and exit

Miscellaneous notes:
* regular expressions engine used here is PCRE, dialect from Python
* is required to pass either --pattern and -replace, or --pattern-and-
replace argument
* if pattern passed to --pattern-and-replace has /g modifier, it
overwrites --count value
* if neither /g modifier nor --count argument is passed, assume that
--count is equal 1
* if only --count is given, this value is used
* if --eval-replace is given, --replace must be valid Python code, where
can be used m variable.m holds MatchObject instance (see:
http://http://docs.python.org/2/library/re.html#match-objects, for
example:
--eval-replace --replace 'm.group(1).lower()'
* regular expressions with non linear search read whole file to yours
computer memory - if file size is bigger then you have memory in your
computer, it fails
* parsing expression passed to --pattern-and-replace argument is very
simple - if you use / as delimiter, then in your expression can't be
used this character anymore. If you need to use same character as
delimiter and in expression, then better use --pattern and --replace
argument

Security notes:
* be carefull with --eval-replace argument. When it's given, value
passed to --replace is eval-ed, so any not safe code will be executed!

Author:
Marcin Sztolcman <[e-mail]> // http://urzenia.net

HomePage:
http://mysz.github.io/subst/

Some examples?
--------------

Simple replace word 'Hello' with 'Hi' in data read from STDIN:

echo 'Hello World!' | subst -s 's/Hello/Hi/' -

Replace every IP address in form: 192.168.1.X (where X is few digits - single octet)
with 192.168.0.X in `/etc/hosts`:

subst -p '(192\.168)\.1\.(10)' -r '\1.0.\2' /etc/hosts

Installation
------------

`subst` should work on any platform where [Python](http://python.org) is available, it means Linux, Windows, MacOS X etc. There is no dependencies, plain Python power :)

To install, go to [GitHub releases](https://github.com/mysz/subst/releases), download newest release, unpack and put somewhere in `PATH` (ie. `~/bin` or `/usr/local/bin`).

If You want to install newest unstable version, then just copy file to your PATH, for example:

curl https://raw.github.com/mysz/subst/master/subst.py > /usr/local/bin/subst

or:

wget https://raw.github.com/mysz/subst/master/subst.py -O /usr/local/bin/subst

Voila!

Authors
-------

Marcin Sztolcman <[e-mail]>

Contact
-------

If you like or dislike this software, please do not hesitate to tell me about this me via email ([e-mail]).

If you find bug or have an idea to enhance this tool, please use GitHub's [issues](https://github.com/mysz/subst/issues).

License
-------

The MIT License (MIT)

Copyright (c) 2013 Marcin Sztolcman

Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
the Software, and to permit persons to whom the Software is furnished to do so,
subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

ChangeLog
---------

### v0.3.1

* prepared and uploaded to PYPI
* typos and editorials

### v0.3

* better handling of non-ascii encoding in files, patterns etc
* higher priority for --pattern-* switches then modifiers in --pattern-and-replace
* unified switches syntax (was --pattern_and_replace, but other switches used dashes)
* pep8
* typos and editorials

### v0.2

* second public version