man : msgfilter
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9.4 Invoking the `msgfilter' Program
msgfilter [OPTION] FILTER [FILTER-OPTION]
The `msgfilter' program applies a filter to all translations of a
During each FILTER invocation, the environment variable
`MSGFILTER_MSGID' is bound to the message's msgid, and the environment
variable `MSGFILTER_LOCATION' is bound to the location in the PO file
of the message. If the message has a context, the environment variable
`MSGFILTER_MSGCTXT' is bound to the message's msgctxt, otherwise it is
9.4.1 Input file location
Input PO file.
Add DIRECTORY to the list of directories. Source files are
searched relative to this list of directories. The resulting `.po'
file will be written relative to the current directory, though.
If no INPUTFILE is given or if it is `-', standard input is read.
9.4.2 Output file location
Write output to specified file.
The results are written to standard output if no output file is
specified or if it is `-'.
9.4.3 The filter
The FILTER can be any program that reads a translation from standard
input and writes a modified translation to standard output. A
frequently used filter is `sed'. A few particular built-in filters are
Note: If the filter is not a built-in filter, you have to care about
encodings: It is your responsibility to ensure that the FILTER can cope
with input encoded in the translation catalog's encoding. If the
FILTER wants input in a particular encoding, you can in a first step
convert the translation catalog to that encoding using the `msgconv'
program, before invoking `msgfilter'. If the FILTER wants input in the
locale's encoding, but you want to avoid the locale's encoding, then
you can first convert the translation catalog to UTF-8 using the
`msgconv' program and then make `msgfilter' work in an UTF-8 locale, by
using the `LC_ALL' environment variable.
Note: Most translations in a translation catalog don't end with a
newline character. For this reason, it is important that the FILTER
recognizes its last input line even if it ends without a newline, and
that it doesn't add an undesired trailing newline at the end. The `sed'
program on some platforms is known to ignore the last line of input if
it is not terminated with a newline. You can use GNU `sed' instead; it
does not have this limitation.
9.4.4 Useful FILTER-OPTIONs when the FILTER is `sed'
Add SCRIPT to the commands to be executed.
Add the contents of SCRIPTFILE to the commands to be executed.
Suppress automatic printing of pattern space.
9.4.5 Built-in FILTERs
The filter `recode-sr-latin' is recognized as a built-in filter.
The command `recode-sr-latin' converts Serbian text, written in the
Cyrillic script, to the Latin script. The command `msgfilter
recode-sr-latin' applies this conversion to the translations of a PO
file. Thus, it can be used to convert an `sr.po' file to an
The use of built-in filters is not sensitive to the current locale's
encoding. Moreover, when used with a built-in filter, `msgfilter' can
automatically convert the message catalog to the UTF-8 encoding when
9.4.6 Input file syntax
Assume the input file is a Java ResourceBundle in Java
`.properties' syntax, not in PO file syntax.
Assume the input file is a NeXTstep/GNUstep localized resource
file in `.strings' syntax, not in PO file syntax.
9.4.7 Output details
Specify whether or when to use colors and other text attributes.
See *note The --color option:: for details.
Specify the CSS style rule file to use for `--color'. See *note
The --style option:: for details.
Always write an output file even if it contains no message.
Write the .po file using indented style.
Keep the header entry, i.e. the message with `msgid ""',
unmodified, instead of filtering it. By default, the header entry
is subject to filtering like any other message.
Do not write `#: FILENAME:LINE' lines.
Generate `#: FILENAME:LINE' lines (default).
Write out a strict Uniforum conforming PO file. Note that this
Uniforum format should be avoided because it doesn't support the
Write out a Java ResourceBundle in Java `.properties' syntax. Note
that this file format doesn't support plural forms and silently
drops obsolete messages.
Write out a NeXTstep/GNUstep localized resource file in `.strings'
syntax. Note that this file format doesn't support plural forms.
Set the output page width. Long strings in the output files will
be split across multiple lines in order to ensure that each line's
width (= number of screen columns) is less or equal to the given
Do not break long message lines. Message lines whose width
exceeds the output page width will not be split into several
lines. Only file reference lines which are wider than the output
page width will be split.
Generate sorted output. Note that using this option makes it much
harder for the translator to understand each message's context.
Sort output by file location.
9.4.8 Informative output
Display this help and exit.
Output version information and exit.
To convert German translations to Swiss orthography (in an UTF-8
msgconv -t UTF-8 de.po | msgfilter sed -e 's/ß/ss/g'
To convert Serbian translations in Cyrillic script to Latin script:
msgfilter recode-sr-latin < sr.po