extract - interactive string extract and replace
extract [ -i ignorefile ] [ -m prefix ] [ -n ] [ -p patternfile ] [ -s string ]
[ -u ] source-program...
The command interactively extracts text strings from source programs. The command replaces the strings it extracts with calls to the func-
tion. The command also writes the string it extracts to a source message catalog. You use this command to replace hard-coded messages
in your program source file with calls to the command and create a source message catalog. At run time, the program reads the message text
from the message catalog. By storing messages in a message catalog, instead of in your program, you allow the text of messages to be
translated to a new language or modified without the source program being changed.
In the source-program argument, you name one or more source programs from which you want messages extracted. The command does not extract
messages from source programs included using the directive. Therefore, you might want to name a source program and all the source programs
it includes on a single command line.
You can create a patterns file (as specified by (patternfile) to control how the command extracts and replaces text. The patterns file is
divided into several sections, each of which is identified by a keyword. The keyword must start at the beginning of a new line, and its
first character must be a dollar sign ($). Following the identifier, you specify a number of patterns. Each pattern begins on a new line
and follows the regular expression syntax you use in the routine. For more information on the patterns file, see the reference page.
In addition to the patterns file, you can create a file that indicates strings that ignores. Each line in this ignore file contains a sin-
gle string to be ignored that follows the syntax of the routine.
When you invoke the command, it reads the patterns file and the file that contains strings it ignores. You can specify a patterns file and
an ignore file on the command line. Otherwise, the command matches all strings and uses a default patterns file.
When you run it displays three windows on your terminal. The first window contains the program source code. The string that matches a
string in the patterns file is displayed in reverse video.
The second window displays the contents of the source message catalog that the command is creating.
The third window contains a list of the commands that are available. The command displays the current command in reverse video. You can
execute the current command by pressing the RETURN key. Select another command by typing the first letter in the command name and pressing
the RETURN key. The command is not sensitive to the case of letters, so you can use uppercase or lowercase letters to issue commands.
You can use the following commands to control how treats the string displayed in the first window:
EXTRACT Extract the string into the catalog file and rewrite the source using the rewrite string in the patterns file.
DUPLICATE If the string has been encountered previously, rewrite the source program using the same message number as before. The com-
mand need not add the message to the source message catalog again, so this command saves space in catalogs.
IGNORE Ignore this and all subsequent occurrences of this string during this interactive session. This command does not add the
string to the ignore file.
PASS Pass by (ignore) this occurrence of this particular string.
ADD Ignore this and all subsequent occurrences of this string during this interactive session. Add the string to the ignore
COMMENT Add the comment you enter to the source message catalog. The command prompts you to be sure the comment you entered is cor-
rect. You answer the prompt by typing ``y,'' n, or q, without pressing the RETURN key.
QUIT Quit from the interactive session. The command prompts you to be sure you want to quit. Answer ``y'' or ``n'' to the
prompt, without pressing the return key.
The output files that creates up to this point are not removed by this command. However, the files contain only the result
of the string extractions that occurred before you issued the QUIT command.
HELP Display a description of all the commands.
The command creates to files in your current working directory. The command creates a new version of the source program that contains
calls to the function, instead of hard-coded messages. The new version of the source program has the same name as the input source pro-
gram, with the prefix ``nl_''. For example, if the input source program is named the output source program is named
In addition to a new source program, the command creates a source message catalog. The source message catalog contains the text for each
message extracted from your input source program. The command names the file by appending ``.msf'' to the name of the input source pro-
gram. For example, the source message catalog for the source program is named You can use the source message catalog as input to the com-
-i Ignore text strings specified in ignorefile . By default, the command searches for ignorefile in the current working directory,
your home directory, and
If you omit the option, recognizes all strings specified in the patterns file.
-m Add prefix to message numbers in the output source program and source message catalog. You can use this prefix as a mnemonic. You
must process source message catalogs that contain message number prefixes using the option.
-n Create a new source message catalog for each input source program. By default, if you specify more than one input source program on
the command line, the command creates one source message catalog for all the input source programs.
-p Use patternfile to match strings in the input source program. By default, the command searches for the pattern file in the current
directory, your home directory and finally
If you omit the option, the command uses a default patterns file that is stored in
-s Write string at the top of the source message catalog. If you omit the option, uses the string specified in the section of the pat-
-u Use a file produced by a previous run of This file contains details of all the strings which matched the pattern file along with file
offsets and line numbers. By default is run and its output is used to drive
Given the current syntax of the patterns file, you cannot cause to ignore strings in comments that are longer than one line.
You can specify only one rewrite string for all classes of pattern matches.
The command does not extract strings from files you include with the directive. You must run the commands on these files separately.
Your terminal screen must contain at least 80 columns and 24 lines for to display its three windows.
The command does not recognize strings that extend beyond one line.
The following example shows the commands you issue to run the command, create a message catalog from the source message catalog, and com-
pile the output source program:
% extract -i newignore -p c_patterns remove.c
% gencat remove.cat remove.msf
% vi nl_remove.c
% cc nl_remove.c
In this example, the command uses the file to determine which strings to ignore. The command uses the file to determines which strings to
match. The input source program is named
In response to this command, creates the source message catalog and the output source program
You must edit to include the appropriate and function calls.
The command creates a message catalog and the command creates an executable program.
intro(3int), gencat(1int), strextract(1int), strmerge(1int), regex(3), catopen(3int), catgets(3int), patterns(5int)
Guide to Developing International Software