Go to the first, previous, next, last section, table of contents.


9 Manipulating PO Files

Sometimes it is necessary to manipulate PO files in a way that is better performed automatically than by hand. GNU gettext includes a complete set of tools for this purpose.

When merging two packages into a single package, the resulting POT file will be the concatenation of the two packages' POT files. Thus the maintainer must concatenate the two existing package translations into a single translation catalog, for each language. This is best performed using ‘msgcat’. It is then the translators' duty to deal with any possible conflicts that arose during the merge.

When a translator takes over the translation job from another translator, but she uses a different character encoding in her locale, she will convert the catalog to her character encoding. This is best done through the ‘msgconv’ program.

When a maintainer takes a source file with tagged messages from another package, he should also take the existing translations for this source file (and not let the translators do the same job twice). One way to do this is through ‘msggrep’, another is to create a POT file for that source file and use ‘msgmerge’.

When a translator wants to adjust some translation catalog for a special dialect or orthography -- for example, German as written in Switzerland versus German as written in Germany -- she needs to apply some text processing to every message in the catalog. The tool for doing this is ‘msgfilter’.

Another use of msgfilter is to produce approximately the POT file for which a given PO file was made. This can be done through a filter command like ‘msgfilter sed -e d | sed -e '/^# /d'’. Note that the original POT file may have had different comments and different plural message counts, that's why it's better to use the original POT file if available.

When a translator wants to check her translations, for example according to orthography rules or using a non-interactive spell checker, she can do so using the ‘msgexec’ program.

When third party tools create PO or POT files, sometimes duplicates cannot be avoided. But the GNU gettext tools give an error when they encounter duplicate msgids in the same file and in the same domain. To merge duplicates, the ‘msguniq’ program can be used.

‘msgcomm’ is a more general tool for keeping or throwing away duplicates, occurring in different files.

‘msgcmp’ can be used to check whether a translation catalog is completely translated.

‘msgattrib’ can be used to select and extract only the fuzzy or untranslated messages of a translation catalog.

‘msgen’ is useful as a first step for preparing English translation catalogs. It copies each message's msgid to its msgstr.

Finally, for those applications where all these various programs are not sufficient, a library ‘libgettextpo’ is provided that can be used to write other specialized programs that process PO files.

9.1 Invoking the msgcat Program

msgcat [option] [inputfile]...

The msgcat program concatenates and merges the specified PO files. It finds messages which are common to two or more of the specified PO files. By using the --more-than option, greater commonality may be requested before messages are printed. Conversely, the --less-than option may be used to specify less commonality before messages are printed (i.e. ‘--less-than=2’ will only print the unique messages). Translations, comments and extract comments will be cumulated, except that if --use-first is specified, they will be taken from the first PO file to define them. File positions from all PO files will be cumulated.

9.1.1 Input file location

inputfile ...’
Input files.
‘-f file
‘--files-from=file
Read the names of the input files from file instead of getting them from the command line.
‘-D directory
‘--directory=directory
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 inputfile is ‘-’, standard input is read.

9.1.2 Output file location

‘-o file
‘--output-file=file
Write output to specified file.

The results are written to standard output if no output file is specified or if it is ‘-’.

9.1.3 Message selection

‘-< number
‘--less-than=number
Print messages with less than number definitions, defaults to infinite if not set.
‘-> number
‘--more-than=number
Print messages with more than number definitions, defaults to 0 if not set.
‘-u’
‘--unique’
Shorthand for ‘--less-than=2’. Requests that only unique messages be printed.

9.1.4 Input file syntax

‘-P’
‘--properties-input’
Assume the input files are Java ResourceBundles in Java .properties syntax, not in PO file syntax.
‘--stringtable-input’
Assume the input files are NeXTstep/GNUstep localized resource files in .strings syntax, not in PO file syntax.

9.1.5 Output details

‘-t’
‘--to-code=name
Specify encoding for output.
‘--use-first’
Use first available translation for each message. Don't merge several translations into one.
‘--color’
‘--color=when
Specify whether or when to use colors and other text attributes. See section 9.11.1 The --color option for details.
‘--style=style_file
Specify the CSS style rule file to use for --color. See section 9.11.3 The --style option for details.
‘--force-po’
Always write an output file even if it contains no message.
‘-i’
‘--indent’
Write the .po file using indented style.
‘--no-location’
Do not write ‘#: filename:line lines.
‘-n’
‘--add-location’
Generate ‘#: filename:line lines (default).
‘--strict’
Write out a strict Uniforum conforming PO file. Note that this Uniforum format should be avoided because it doesn't support the GNU extensions.
‘-p’
‘--properties-output’
Write out a Java ResourceBundle in Java .properties syntax. Note that this file format doesn't support plural forms and silently drops obsolete messages.
‘--stringtable-output’
Write out a NeXTstep/GNUstep localized resource file in .strings syntax. Note that this file format doesn't support plural forms.
‘-w number
‘--width=number
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 number.
‘--no-wrap’
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.
‘-s’
‘--sort-output’
Generate sorted output. Note that using this option makes it much harder for the translator to understand each message's context.
‘-F’
‘--sort-by-file’
Sort output by file location.

9.1.6 Informative output

‘-h’
‘--help’
Display this help and exit.
‘-V’
‘--version’
Output version information and exit.

9.2 Invoking the msgconv Program

msgconv [option] [inputfile]

The msgconv program converts a translation catalog to a different character encoding.

9.2.1 Input file location

inputfile
Input PO file.
‘-D directory
‘--directory=directory
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.

9.2.2 Output file location

‘-o file
‘--output-file=file
Write output to specified file.

The results are written to standard output if no output file is specified or if it is ‘-’.

9.2.3 Conversion target

‘-t’
‘--to-code=name
Specify encoding for output.

The default encoding is the current locale's encoding.

9.2.4 Input file syntax

‘-P’
‘--properties-input’
Assume the input file is a Java ResourceBundle in Java .properties syntax, not in PO file syntax.
‘--stringtable-input’
Assume the input file is a NeXTstep/GNUstep localized resource file in .strings syntax, not in PO file syntax.

9.2.5 Output details

‘--force-po’
Always write an output file even if it contains no message.
‘-i’
‘--indent’
Write the .po file using indented style.
‘--no-location’
Do not write ‘#: filename:line lines.
‘--add-location’
Generate ‘#: filename:line lines (default).
‘--strict’
Write out a strict Uniforum conforming PO file. Note that this Uniforum format should be avoided because it doesn't support the GNU extensions.
‘-p’
‘--properties-output’
Write out a Java ResourceBundle in Java .properties syntax. Note that this file format doesn't support plural forms and silently drops obsolete messages.
‘--stringtable-output’
Write out a NeXTstep/GNUstep localized resource file in .strings syntax. Note that this file format doesn't support plural forms.
‘-w number
‘--width=number
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 number.
‘--no-wrap’
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.
‘-s’
‘--sort-output’
Generate sorted output. Note that using this option makes it much harder for the translator to understand each message's context.
‘-F’
‘--sort-by-file’
Sort output by file location.

9.2.6 Informative output

‘-h’
‘--help’
Display this help and exit.
‘-V’
‘--version’
Output version information and exit.

9.3 Invoking the msggrep Program

msggrep [option] [inputfile]

The msggrep program extracts all messages of a translation catalog that match a given pattern or belong to some given source files.

9.3.1 Input file location

inputfile
Input PO file.
‘-D directory
‘--directory=directory
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.

9.3.2 Output file location

‘-o file
‘--output-file=file
Write output to specified file.

The results are written to standard output if no output file is specified or if it is ‘-’.

9.3.3 Message selection

  [-N sourcefile]... [-M domainname]...
  [-J msgctxt-pattern] [-K msgid-pattern] [-T msgstr-pattern]
  [-C comment-pattern]

A message is selected if

When more than one selection criterion is specified, the set of selected messages is the union of the selected messages of each criterion.

msgctxt-pattern or msgid-pattern or msgstr-pattern syntax:

  [-E | -F] [-e pattern | -f file]...

patterns are basic regular expressions by default, or extended regular expressions if -E is given, or fixed strings if -F is given.

‘-N sourcefile
‘--location=sourcefile
Select messages extracted from sourcefile. sourcefile can be either a literal file name or a wildcard pattern.
‘-M domainname
‘--domain=domainname
Select messages belonging to domain domainname.
‘-J’
‘--msgctxt’
Start of patterns for the msgctxt.
‘-K’
‘--msgid’
Start of patterns for the msgid.
‘-T’
‘--msgstr’
Start of patterns for the msgstr.
‘-C’
‘--comment’
Start of patterns for the translator's comment.
‘-X’
‘--extracted-comment’
Start of patterns for the extracted comments.
‘-E’
‘--extended-regexp’
Specify that pattern is an extended regular expression.
‘-F’
‘--fixed-strings’
Specify that pattern is a set of newline-separated strings.
‘-e pattern
‘--regexp=pattern
Use pattern as a regular expression.
‘-f file
‘--file=file
Obtain pattern from file.
‘-i’
‘--ignore-case’
Ignore case distinctions.
‘-v’
‘--invert-match’
Output only the messages that do not match any selection criterion, instead of the messages that match a selection criterion.

9.3.4 Input file syntax

‘-P’
‘--properties-input’
Assume the input file is a Java ResourceBundle in Java .properties syntax, not in PO file syntax.
‘--stringtable-input’
Assume the input file is a NeXTstep/GNUstep localized resource file in .strings syntax, not in PO file syntax.

9.3.5 Output details

‘--force-po’
Always write an output file even if it contains no message.
‘--indent’
Write the .po file using indented style.
‘--no-location’
Do not write ‘#: filename:line lines.
‘--add-location’
Generate ‘#: filename:line lines (default).
‘--strict’
Write out a strict Uniforum conforming PO file. Note that this Uniforum format should be avoided because it doesn't support the GNU extensions.
‘-p’
‘--properties-output’
Write out a Java ResourceBundle in Java .properties syntax. Note that this file format doesn't support plural forms and silently drops obsolete messages.
‘--stringtable-output’
Write out a NeXTstep/GNUstep localized resource file in .strings syntax. Note that this file format doesn't support plural forms.
‘-w number
‘--width=number
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 number.
‘--no-wrap’
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.
‘--sort-output’
Generate sorted output. Note that using this option makes it much harder for the translator to understand each message's context.
‘--sort-by-file’
Sort output by file location.

9.3.6 Informative output

‘-h’
‘--help’
Display this help and exit.
‘-V’
‘--version’
Output version information and exit.

9.3.7 Examples

To extract the messages that come from the source files gnulib-lib/error.c and gnulib-lib/getopt.c:

msggrep -N gnulib-lib/error.c -N gnulib-lib/getopt.c input.po

To extract the messages that contain the string “Please specify” in the original string:

msggrep --msgid -F -e 'Please specify' input.po

To extract the messages that have a context specifier of either “Menu>File” or “Menu>Edit” or a submenu of them:

msggrep --msgctxt -E -e '^Menu>(File|Edit)' input.po

To extract the messages whose translation contains one of the strings in the file wordlist.txt:

msggrep --msgstr -F -f wordlist.txt input.po

9.4 Invoking the msgfilter Program

msgfilter [option] filter [filter-option]

The msgfilter program applies a filter to all translations of a translation catalog.

9.4.1 Input file location

‘-i inputfile
‘--input=inputfile
Input PO file.
‘-D directory
‘--directory=directory
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

‘-o file
‘--output-file=file
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 also recognized.

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’

‘-e script
‘--expression=script
Add script to the commands to be executed.
‘-f scriptfile
‘--file=scriptfile
Add the contents of scriptfile to the commands to be executed.
‘-n’
‘--quiet’
‘--silent’
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 ‘sr@latin.po’ file.

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 needed.

9.4.6 Input file syntax

‘-P’
‘--properties-input’
Assume the input file is a Java ResourceBundle in Java .properties syntax, not in PO file syntax.
‘--stringtable-input’
Assume the input file is a NeXTstep/GNUstep localized resource file in .strings syntax, not in PO file syntax.

9.4.7 Output details

‘--force-po’
Always write an output file even if it contains no message.
‘--indent’
Write the .po file using indented style.
‘--keep-header’
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.
‘--no-location’
Do not write ‘#: filename:line lines.
‘--add-location’
Generate ‘#: filename:line lines (default).
‘--strict’
Write out a strict Uniforum conforming PO file. Note that this Uniforum format should be avoided because it doesn't support the GNU extensions.
‘-p’
‘--properties-output’
Write out a Java ResourceBundle in Java .properties syntax. Note that this file format doesn't support plural forms and silently drops obsolete messages.
‘--stringtable-output’
Write out a NeXTstep/GNUstep localized resource file in .strings syntax. Note that this file format doesn't support plural forms.
‘-w number
‘--width=number
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 number.
‘--no-wrap’
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.
‘-s’
‘--sort-output’
Generate sorted output. Note that using this option makes it much harder for the translator to understand each message's context.
‘-F’
‘--sort-by-file’
Sort output by file location.

9.4.8 Informative output

‘-h’
‘--help’
Display this help and exit.
‘-V’
‘--version’
Output version information and exit.

9.4.9 Examples

To convert German translations to Swiss orthography (in an UTF-8 locale):

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

9.5 Invoking the msguniq Program

msguniq [option] [inputfile]

The msguniq program unifies duplicate translations in a translation catalog. It finds duplicate translations of the same message ID. Such duplicates are invalid input for other programs like msgfmt, msgmerge or msgcat. By default, duplicates are merged together. When using the ‘--repeated’ option, only duplicates are output, and all other messages are discarded. Comments and extracted comments will be cumulated, except that if ‘--use-first’ is specified, they will be taken from the first translation. File positions will be cumulated. When using the ‘--unique’ option, duplicates are discarded.

9.5.1 Input file location

inputfile
Input PO file.
‘-D directory
‘--directory=directory
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.

9.5.2 Output file location

‘-o file
‘--output-file=file
Write output to specified file.

The results are written to standard output if no output file is specified or if it is ‘-’.

9.5.3 Message selection

‘-d’
‘--repeated’
Print only duplicates.
‘-u’
‘--unique’
Print only unique messages, discard duplicates.

9.5.4 Input file syntax

‘-P’
‘--properties-input’
Assume the input file is a Java ResourceBundle in Java .properties syntax, not in PO file syntax.
‘--stringtable-input’
Assume the input file is a NeXTstep/GNUstep localized resource file in .strings syntax, not in PO file syntax.

9.5.5 Output details

‘-t’
‘--to-code=name
Specify encoding for output.
‘--use-first’
Use first available translation for each message. Don't merge several translations into one.
‘--force-po’
Always write an output file even if it contains no message.
‘-i’
‘--indent’
Write the .po file using indented style.
‘--no-location’
Do not write ‘#: filename:line lines.
‘-n’
‘--add-location’
Generate ‘#: filename:line lines (default).
‘--strict’
Write out a strict Uniforum conforming PO file. Note that this Uniforum format should be avoided because it doesn't support the GNU extensions.
‘-p’
‘--properties-output’
Write out a Java ResourceBundle in Java .properties syntax. Note that this file format doesn't support plural forms and silently drops obsolete messages.
‘--stringtable-output’
Write out a NeXTstep/GNUstep localized resource file in .strings syntax. Note that this file format doesn't support plural forms.
‘-w number
‘--width=number
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 number.
‘--no-wrap’
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.
‘-s’
‘--sort-output’
Generate sorted output. Note that using this option makes it much harder for the translator to understand each message's context.
‘-F’
‘--sort-by-file’
Sort output by file location.

9.5.6 Informative output

‘-h’
‘--help’
Display this help and exit.
‘-V’
‘--version’
Output version information and exit.

9.6 Invoking the msgcomm Program

msgcomm [option] [inputfile]...

The msgcomm program finds messages which are common to two or more of the specified PO files. By using the --more-than option, greater commonality may be requested before messages are printed. Conversely, the --less-than option may be used to specify less commonality before messages are printed (i.e. ‘--less-than=2’ will only print the unique messages). Translations, comments and extract comments will be preserved, but only from the first PO file to define them. File positions from all PO files will be cumulated.

9.6.1 Input file location

inputfile ...’
Input files.
‘-f file
‘--files-from=file
Read the names of the input files from file instead of getting them from the command line.
‘-D directory
‘--directory=directory
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 inputfile is ‘-’, standard input is read.

9.6.2 Output file location

‘-o file
‘--output-file=file
Write output to specified file.

The results are written to standard output if no output file is specified or if it is ‘-’.

9.6.3 Message selection

‘-< number
‘--less-than=number
Print messages with less than number definitions, defaults to infinite if not set.
‘-> number
‘--more-than=number
Print messages with more than number definitions, defaults to 1 if not set.
‘-u’
‘--unique’
Shorthand for ‘--less-than=2’. Requests that only unique messages be printed.

9.6.4 Input file syntax

‘-P’
‘--properties-input’
Assume the input files are Java ResourceBundles in Java .properties syntax, not in PO file syntax.
‘--stringtable-input’
Assume the input files are NeXTstep/GNUstep localized resource files in .strings syntax, not in PO file syntax.

9.6.5 Output details

‘--force-po’
Always write an output file even if it contains no message.
‘-i’
‘--indent’
Write the .po file using indented style.
‘--no-location’
Do not write ‘#: filename:line lines.
‘-n’
‘--add-location’
Generate ‘#: filename:line lines (default).
‘--strict’
Write out a strict Uniforum conforming PO file. Note that this Uniforum format should be avoided because it doesn't support the GNU extensions.
‘-p’
‘--properties-output’
Write out a Java ResourceBundle in Java .properties syntax. Note that this file format doesn't support plural forms and silently drops obsolete messages.
‘--stringtable-output’
Write out a NeXTstep/GNUstep localized resource file in .strings syntax. Note that this file format doesn't support plural forms.
‘-w number
‘--width=number
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 number.
‘--no-wrap’
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.
‘-s’
‘--sort-output’
Generate sorted output. Note that using this option makes it much harder for the translator to understand each message's context.
‘-F’
‘--sort-by-file’
Sort output by file location.
‘--omit-header’
Don't write header with ‘msgid ""’ entry.

9.6.6 Informative output

‘-h’
‘--help’
Display this help and exit.
‘-V’
‘--version’
Output version information and exit.

9.7 Invoking the msgcmp Program

msgcmp [option] def.po ref.pot

The msgcmp program compares two Uniforum style .po files to check that both contain the same set of msgid strings. The def.po file is an existing PO file with the translations. The ref.pot file is the last created PO file, or a PO Template file (generally created by xgettext). This is useful for checking that you have translated each and every message in your program. Where an exact match cannot be found, fuzzy matching is used to produce better diagnostics.

9.7.1 Input file location

def.po’
Translations.
ref.pot’
References to the sources.
‘-D directory
‘--directory=directory
Add directory to the list of directories. Source files are searched relative to this list of directories.

9.7.2 Operation modifiers

‘-m’
‘--multi-domain’
Apply ref.pot to each of the domains in def.po.
‘--use-fuzzy’
Consider fuzzy messages in the def.po file like translated messages. Note that using this option is usually wrong, because fuzzy messages are exactly those which have not been validated by a human translator.
‘--use-untranslated’
Consider untranslated messages in the def.po file like translated messages. Note that using this option is usually wrong.

9.7.3 Input file syntax

‘-P’
‘--properties-input’
Assume the input files are Java ResourceBundles in Java .properties syntax, not in PO file syntax.
‘--stringtable-input’
Assume the input files are NeXTstep/GNUstep localized resource files in .strings syntax, not in PO file syntax.

9.7.4 Informative output

‘-h’
‘--help’
Display this help and exit.
‘-V’
‘--version’
Output version information and exit.

9.8 Invoking the msgattrib Program

msgattrib [option] [inputfile]

The msgattrib program filters the messages of a translation catalog according to their attributes, and manipulates the attributes.

9.8.1 Input file location

inputfile
Input PO file.
‘-D directory
‘--directory=directory
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.

9.8.2 Output file location

‘-o file
‘--output-file=file
Write output to specified file.

The results are written to standard output if no output file is specified or if it is ‘-’.

9.8.3 Message selection

‘--translated’
Keep translated messages, remove untranslated messages.
‘--untranslated’
Keep untranslated messages, remove translated messages.
‘--no-fuzzy’
Remove ‘fuzzy’ marked messages.
‘--only-fuzzy’
Keep ‘fuzzy’ marked messages, remove all other messages.
‘--no-obsolete’
Remove obsolete #~ messages.
‘--only-obsolete’
Keep obsolete #~ messages, remove all other messages.

9.8.4 Attribute manipulation

Attributes are modified after the message selection/removal has been performed. If the ‘--only-file’ or ‘--ignore-file’ option is specified, the attribute modification is applied only to those messages that are listed in the only-file and not listed in the ignore-file.

‘--set-fuzzy’
Set all messages ‘fuzzy’.
‘--clear-fuzzy’
Set all messages non-‘fuzzy’.
‘--set-obsolete’
Set all messages obsolete.
‘--clear-obsolete’
Set all messages non-obsolete.
‘--clear-previous’
Remove the “previous msgid” (‘#|’) comments from all messages.
‘--only-file=file
Limit the attribute changes to entries that are listed in file. file should be a PO or POT file.
‘--ignore-file=file
Limit the attribute changes to entries that are not listed in file. file should be a PO or POT file.
‘--fuzzy’
Synonym for ‘--only-fuzzy --clear-fuzzy’: It keeps only the fuzzy messages and removes their ‘fuzzy’ mark.
‘--obsolete’
Synonym for ‘--only-obsolete --clear-obsolete’: It keeps only the obsolete messages and makes them non-obsolete.

9.8.5 Input file syntax

‘-P’
‘--properties-input’
Assume the input file is a Java ResourceBundle in Java .properties syntax, not in PO file syntax.
‘--stringtable-input’
Assume the input file is a NeXTstep/GNUstep localized resource file in .strings syntax, not in PO file syntax.

9.8.6 Output details

‘--force-po’
Always write an output file even if it contains no message.
‘-i’
‘--indent’
Write the .po file using indented style.
‘--no-location’
Do not write ‘#: filename:line lines.
‘-n’
‘--add-location’
Generate ‘#: filename:line lines (default).
‘--strict’
Write out a strict Uniforum conforming PO file. Note that this Uniforum format should be avoided because it doesn't support the GNU extensions.
‘-p’
‘--properties-output’
Write out a Java ResourceBundle in Java .properties syntax. Note that this file format doesn't support plural forms and silently drops obsolete messages.
‘--stringtable-output’
Write out a NeXTstep/GNUstep localized resource file in .strings syntax. Note that this file format doesn't support plural forms.
‘-w number
‘--width=number
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 number.
‘--no-wrap’
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.
‘-s’
‘--sort-output’
Generate sorted output. Note that using this option makes it much harder for the translator to understand each message's context.
‘-F’
‘--sort-by-file’
Sort output by file location.

9.8.7 Informative output

‘-h’
‘--help’
Display this help and exit.
‘-V’
‘--version’
Output version information and exit.

9.9 Invoking the msgen Program

msgen [option] inputfile

The msgen program creates an English translation catalog. The input file is the last created English PO file, or a PO Template file (generally created by xgettext). Untranslated entries are assigned a translation that is identical to the msgid.

Note: ‘msginit --no-translator --locale=en’ performs a very similar task. The main difference is that msginit cares specially about the header entry, whereas msgen doesn't.

9.9.1 Input file location

inputfile
Input PO or POT file.
‘-D directory
‘--directory=directory
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 inputfile is ‘-’, standard input is read.

9.9.2 Output file location

‘-o file
‘--output-file=file
Write output to specified file.

The results are written to standard output if no output file is specified or if it is ‘-’.

9.9.3 Input file syntax

‘-P’
‘--properties-input’
Assume the input file is a Java ResourceBundle in Java .properties syntax, not in PO file syntax.
‘--stringtable-input’
Assume the input file is a NeXTstep/GNUstep localized resource file in .strings syntax, not in PO file syntax.

9.9.4 Output details

‘--force-po’
Always write an output file even if it contains no message.
‘-i’
‘--indent’
Write the .po file using indented style.
‘--no-location’
Do not write ‘#: filename:line lines.
‘--add-location’
Generate ‘#: filename:line lines (default).
‘--strict’
Write out a strict Uniforum conforming PO file. Note that this Uniforum format should be avoided because it doesn't support the GNU extensions.
‘-p’
‘--properties-output’
Write out a Java ResourceBundle in Java .properties syntax. Note that this file format doesn't support plural forms and silently drops obsolete messages.
‘--stringtable-output’
Write out a NeXTstep/GNUstep localized resource file in .strings syntax. Note that this file format doesn't support plural forms.
‘-w number
‘--width=number
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 number.
‘--no-wrap’
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.
‘-s’
‘--sort-output’
Generate sorted output. Note that using this option makes it much harder for the translator to understand each message's context.
‘-F’
‘--sort-by-file’
Sort output by file location.

9.9.5 Informative output

‘-h’
‘--help’
Display this help and exit.
‘-V’
‘--version’
Output version information and exit.

9.10 Invoking the msgexec Program

msgexec [option] command [command-option]

The msgexec program applies a command to all translations of a translation catalog. The command can be any program that reads a translation from standard input. It is invoked once for each translation. Its output becomes msgexec's output. msgexec's return code is the maximum return code across all invocations.

A special builtin command called ‘0’ outputs the translation, followed by a null byte. The output of ‘msgexec 0’ is suitable as input for ‘xargs -0’.

During each command invocation, the environment variable MSGEXEC_MSGID is bound to the message's msgid, and the environment variable MSGEXEC_LOCATION is bound to the location in the PO file of the message. If the message has a context, the environment variable MSGEXEC_MSGCTXT is bound to the message's msgctxt, otherwise it is unbound.

Note: It is your responsibility to ensure that the command can cope with input encoded in the translation catalog's encoding. If the command 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 ‘msgexec’. If the command 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 ‘msgexec’ work in an UTF-8 locale, by using the LC_ALL environment variable.

9.10.1 Input file location

‘-i inputfile
‘--input=inputfile
Input PO file.
‘-D directory
‘--directory=directory
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.

9.10.2 Input file syntax

‘-P’
‘--properties-input’
Assume the input file is a Java ResourceBundle in Java .properties syntax, not in PO file syntax.
‘--stringtable-input’
Assume the input file is a NeXTstep/GNUstep localized resource file in .strings syntax, not in PO file syntax.

9.10.3 Informative output

‘-h’
‘--help’
Display this help and exit.
‘-V’
‘--version’
Output version information and exit.

9.11 Highlighting parts of PO files

Translators are usually only interested in seeing the untranslated and fuzzy messages of a PO file. Also, when a message is set fuzzy because the msgid changed, they want to see the differences between the previous msgid and the current one (especially if the msgid is long and only few words in it have changed). Finally, it's always welcome to highlight the different sections of a message in a PO file (comments, msgid, msgstr, etc.).

Such highlighting is possible through the msgcat options ‘--color’ and ‘--style’.

9.11.1 The --color option

The ‘--color=when option specifies under which conditions colorized output should be generated. The when part can be one of the following:

always
yes
The output will be colorized.
never
no
The output will not be colorized.
auto
tty
The output will be colorized if the output device is a tty, i.e. when the output goes directly to a text screen or terminal emulator window.
html
The output will be colorized and be in HTML format.

‘--color’ is equivalent to ‘--color=yes’. The default is ‘--color=auto’.

Thus, a command like ‘msgcat vi.po’ will produce colorized output when called by itself in a command window. Whereas in a pipe, such as ‘msgcat vi.po | less -R’, it will not produce colorized output. To get colorized output in this situation nevertheless, use the command ‘msgcat --color vi.po | less -R’.

The ‘--color=html’ option will produce output that can be viewed in a browser. This can be useful, for example, for Indic languages, because the renderic of Indic scripts in browser is usually better than in terminal emulators.

Note that the output produced with the --color option is not a valid PO file in itself. It contains additional terminal-specific escape sequences or HTML tags. A PO file reader will give a syntax error when confronted with such content. Except for the ‘--color=html’ case, you therefore normally don't need to save output produced with the --color option in a file.

9.11.2 The environment variable TERM

The environment variable TERM contains a identifier for the text window's capabilities. You can get a detailed list of these cababilities by using the ‘infocmp’ command, using ‘man 5 terminfo’ as a reference.

When producing text with embedded color directives, msgcat looks at the TERM variable. Text windows today typically support at least 8 colors. Often, however, the text window supports 16 or more colors, even though the TERM variable is set to a identifier denoting only 8 supported colors. It can be worth setting the TERM variable to a different value in these cases:

xterm
xterm is in most cases built with support for 16 colors. It can also be built with support for 88 or 256 colors (but not both). You can try to set TERM to either xterm-16color, xterm-88color, or xterm-256color.
rxvt
rxvt is often built with support for 16 colors. You can try to set TERM to rxvt-16color.
konsole
konsole too is often built with support for 16 colors. You can try to set TERM to konsole-16color or xterm-16color.

After setting TERM, you can verify it by invoking ‘msgcat --color=test’ and seeing whether the output looks like a reasonable color map.

9.11.3 The --style option

The ‘--style=style_file option specifies the style file to use when colorizing. It has an effect only when the --color option is effective.

If the --style option is not specified, the environment variable PO_STYLE is considered. It is meant to point to the user's preferred style for PO files.

The default style file is ‘$prefix/share/gettext/styles/po-default.css’, where $prefix is the installation location.

A few style files are predefined:

‘po-vim.css’
This style imitates the look used by vim 7.
‘po-emacs-x.css’
This style imitates the look used by GNU Emacs 21 and 22 in an X11 window.
‘po-emacs-xterm.css’
‘po-emacs-xterm16.css’
‘po-emacs-xterm256.css’
This style imitates the look used by GNU Emacs 22 in a terminal of type ‘xterm’ (8 colors) or ‘xterm-16color’ (16 colors) or ‘xterm-256color’ (256 colors), respectively.

You can use these styles without specifying a directory. They are actually located in ‘$prefix/share/gettext/styles/’, where $prefix is the installation location.

You can also design your own styles. This is described in the next section.

9.11.4 Style rules for PO files

The same style file can be used for styling of a PO file, for terminal output and for HTML output. It is written in CSS (Cascading Style Sheet) syntax. See http://www.w3.org/TR/css2/cover.html for a formal definition of CSS. Many HTML authoring tutorials also contain explanations of CSS.

In the case of HTML output, the style file is embedded in the HTML output. In the case of text output, the style file is interpreted by the msgcat program. This means, in particular, that when @import is used with relative file names, the file names are

CSS rules are built up from selectors and declarations. The declarations specify graphical properties; the selectors specify specify when they apply.

In PO files, the following simple selectors (based on "CSS classes", see the CSS2 spec, section 5.8.3) are supported.

These selectors can be combined to hierarchical selectors. For example,

.msgstr .invalid-format-directive { color: red; }

will highlight the invalid format directives in the translated strings.

In text mode, pseudo-classes (CSS2 spec, section 5.11) and pseudo-elements (CSS2 spec, section 5.12) are not supported.

The declarations in HTML mode are not limited; any graphical attribute supported by the browsers can be used.

The declarations in text mode are limited to the following properties. Other properties will be silently ignored.

color (CSS2 spec, section 14.1)
background-color (CSS2 spec, section 14.2.1)
These properties is supported. Colors will be adjusted to match the terminal's capabilities. Note that many terminals support only 8 colors.
font-weight (CSS2 spec, section 15.2.3)
This property is supported, but most terminals can only render two different weights: normal and bold. Values >= 600 are rendered as bold.
font-style (CSS2 spec, section 15.2.3)
This property is supported. The values italic and oblique are rendered the same way.
text-decoration (CSS2 spec, section 16.3.1)
This property is supported, limited to the values none and underline.

9.11.5 Customizing less for viewing PO files

The ‘less’ program is a popular text file browser for use in a text screen or terminal emulator. It also supports text with embedded escape sequences for colors and text decorations.

You can use less to view a PO file like this (assuming an UTF-8 environment):

msgcat --to-code=UTF-8 --color xyz.po | less -R

You can simplify this to this simple command:

less xyz.po

after these three preparations:

  1. Add the options ‘-R’ and ‘-f’ to the LESS environment variable. In sh shells:
    $ LESS="$LESS -R -f"
    $ export LESS
    
  2. If your system does not already have the ‘lessopen.sh’ and ‘lessclose.sh’ scripts, create them and set the LESSOPEN and LESSCLOSE environment variables, as indicated in the manual page (‘man less’).
  3. Add to ‘lessopen.sh’ a piece of script that recognizes PO files through their file extension and invokes msgcat on them, producing a temporary file. Like this:
    case "$1" in
      *.po)
        tmpfile=`mktemp "${TMPDIR-/tmp}/less.XXXXXX"`
        msgcat --to-code=UTF-8 --color "$1" > "$tmpfile"
        echo "$tmpfile"
        exit 0
        ;;
    esac
    

9.12 Writing your own programs that process PO files

For the tasks for which a combination of ‘msgattrib’, ‘msgcat’ etc. is not sufficient, a set of C functions is provided in a library, to make it possible to process PO files in your own programs. When you use this library, you don't need to write routines to parse the PO file; instead, you retrieve a pointer in memory to each of messages contained in the PO file. Functions for writing PO files are not provided at this time.

The functions are declared in the header file ‘<gettext-po.h>’, and are defined in a library called ‘libgettextpo’.

Data Type: po_file_t
This is a pointer type that refers to the contents of a PO file, after it has been read into memory.

Data Type: po_message_iterator_t
This is a pointer type that refers to an iterator that produces a sequence of messages.

Data Type: po_message_t
This is a pointer type that refers to a message of a PO file, including its translation.

Function: po_file_t po_file_read (const char *filename)
The po_file_read function reads a PO file into memory. The file name is given as argument. The return value is a handle to the PO file's contents, valid until po_file_free is called on it. In case of error, the return value is NULL, and errno is set.

Function: void po_file_free (po_file_t file)
The po_file_free function frees a PO file's contents from memory, including all messages that are only implicitly accessible through iterators.

Function: const char * const * po_file_domains (po_file_t file)
The po_file_domains function returns the domains for which the given PO file has messages. The return value is a NULL terminated array which is valid as long as the file handle is valid. For PO files which contain no ‘domain’ directive, the return value contains only one domain, namely the default domain "messages".

Function: po_message_iterator_t po_message_iterator (po_file_t file, const char *domain)
The po_message_iterator returns an iterator that will produce the messages of file that belong to the given domain. If domain is NULL, the default domain is used instead. To list the messages, use the function po_next_message repeatedly.

Function: void po_message_iterator_free (po_message_iterator_t iterator)
The po_message_iterator_free function frees an iterator previously allocated through the po_message_iterator function.

Function: po_message_t po_next_message (po_message_iterator_t iterator)
The po_next_message function returns the next message from iterator and advances the iterator. It returns NULL when the iterator has reached the end of its message list.

The following functions returns details of a po_message_t. Recall that the results are valid as long as the file handle is valid.

Function: const char * po_message_msgid (po_message_t message)
The po_message_msgid function returns the msgid (untranslated English string) of a message. This is guaranteed to be non-NULL.

Function: const char * po_message_msgid_plural (po_message_t message)
The po_message_msgid_plural function returns the msgid_plural (untranslated English plural string) of a message with plurals, or NULL for a message without plural.

Function: const char * po_message_msgstr (po_message_t message)
The po_message_msgstr function returns the msgstr (translation) of a message. For an untranslated message, the return value is an empty string.

Function: const char * po_message_msgstr_plural (po_message_t message, int index)
The po_message_msgstr_plural function returns the msgstr[index] of a message with plurals, or NULL when the index is out of range or for a message without plural.

Here is an example code how these functions can be used.

const char *filename = ...;
po_file_t file = po_file_read (filename);

if (file == NULL)
  error (EXIT_FAILURE, errno, "couldn't open the PO file %s", filename);
{
  const char * const *domains = po_file_domains (file);
  const char * const *domainp;

  for (domainp = domains; *domainp; domainp++)
    {
      const char *domain = *domainp;
      po_message_iterator_t iterator = po_message_iterator (file, domain);

      for (;;)
        {
          po_message_t *message = po_next_message (iterator);

          if (message == NULL)
            break;
          {
            const char *msgid = po_message_msgid (message);
            const char *msgstr = po_message_msgstr (message);

            ...
          }
        }
      po_message_iterator_free (iterator);
    }
}
po_file_free (file);


Go to the first, previous, next, last section, table of contents.