Content-type: text/html Man page of extract


Section: User Commands (1)
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extract - interactive string extract and replace  


extract [-i ignorefile] [-m prefix] [-n] [-p patternfile] [-s string] [-u] source-program...



Ignore text strings specified in ignorefile. By default, the extract command searches for ignorefile in the current working directory, your home directory, and /usr/lib/nls.

If you omit the -i option, extract recognizes all strings specified in the patterns file. 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 mkcatdefs command. Create a new source message catalog for each input source program. By default, if you specify more than one input source program on the extract command line, the command creates one source message catalog for all the input source programs. 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 /usr/lib/nls.
If you omit the -p option, the extract command uses a default patterns file that is stored in /usr/lib/nls/patterns. Write string at the top of the source message catalog. If you omit the -s option, extract uses the string specified in the $CATHEAD section of the patterns file. Use a message file produced by a previous run of strextract. This file contains details of all the strings which matched the pattern file along with file offsets and line numbers. By default strextract is run and its output is used to drive extract.


The extract command interactively extracts text strings from source programs. The extract command replaces the strings it extracts with calls to the catgets function. 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 catgets 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 extract command does not extract messages from source programs included using the #include directive. Therefore, you might want to name a source program and all the source programs it includes on a single extract command line.

You can create a patterns file (as specified by patternfile) to control how the extract 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 regexp routine. For more information on the patterns file, see patterns(4)and for more information on the regexp routine, see regexp(3).

In addition to the patterns file, you can create a file that indicates strings that extract ignores. Each line in this ignore file contains a single string to be ignored that follows the syntax of the regexp routine.

When you invoke the extract 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 extract command line. Otherwise, the extract command matches all strings and uses a default patterns file.

When you run extract, 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 extract command is creating.

The third window contains a list of the commands that are available. The extract 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 extract 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 extract treats the string displayed in the first window: Extract the string into the catalog file and rewrite the source using the rewrite string in the patterns file. If the string has been encountered previously, rewrite the source program using the same message number as before. The extract command need not add the message to the source message catalog again, so this command saves space in catalogs. 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 by (ignore) this occurrence of this particular string. Ignore this and all subsequent occurrences of this string during this interactive session. Add the string to the ignore file. Add the comment you enter to the source message catalog. The extract command prompts you to be sure the comment you entered is correct. You answer the prompt by typing ``y,'' ``n,'' or ``q,'' without pressing the RETURN key. Quit from the interactive session. The extract 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 extract 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. Display a description of all the extract commands.

The extract command creates two files in your current working directory. The command creates a new version of the source program that contains calls to the catgets function, instead of hard-coded messages. The new version of the source program has the same name as the input source program, with the prefix nl_. For example, if the input source program is named update.c, the output source program is named nl_update.c.

In addition to a new source program, the extract command creates a source message catalog. The source message catalog contains the text for each message extracted from your input source program. The extract command names the file by appending .msg to the name of the input source program. For example, the source message catalog for the update.c source program is named update.msg. You can use the source message catalog as input to the gencat command.


Given the current syntax of the patterns file, you cannot cause extract 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 extract command does not extract strings from files you include with the #include directive. You must run the extract commands on these files separately.

Your terminal screen must contain at least 80 columns and 24 lines for extract to display its three windows.

The extract command does not recognize strings that extend beyond one line.


The following example shows the commands you issue to run the extract command, create a message catalog from the source message catalog, and compile the output source program:

% extract -i newignore -p c_patterns remove.c % gencat remove.msg % vi nl_remove.c % cc nl_remove.c

In this example, the extract command uses the newignore file to determine which strings to ignore. The command uses the c_patterns file to determines which strings to match. The input source program is named remove.c.

In response to this command, extract creates the source message catalog remove.msg and the output source program nl_remove.c.

You must edit nl_remove.c to include the appropriate catopen and catclose function calls.

The gencat command creates a message catalog and the cc command creates an executable program.


gencat(1), mkcatdefs(1), strextract(1), strmerge(1), catopen(3), catgets(3), regexp(3), patterns(4)

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Time: 02:42:48 GMT, October 02, 2010