Provided by: runawk_1.6.0-2_amd64 bug

NAME

       runawk - wrapper for AWK interpreter

SYNOPSIS

       runawk [options] program_file

       runawk -e program

MOTIVATION

       After years of using AWK for programming I've found that despite of its simplicity and
       limitations AWK is good enough for scripting a wide range of different tasks. AWK is not
       as poweful as their bigger counterparts like Perl, Ruby, TCL and others but it has their
       own advantages like compactness, simplicity and availability on almost all UNIX-like
       systems. I personally also like its data-driven nature and token orientation, very useful
       techniques for text processing utilities.

       Unfortunately awk interpreters lacks some important features and sometimes do not work as
       good as they could do.

       Problems I see (some of them, of course)

       1.
         AWK lacks support for modules. Even if I create small programs, I often want to use
         functions created earlier and already used in other scripts. That is, it whould great to
         organise functions into so called libraries (modules).

       2.
         In order to pass arguments to "#!/usr/bin/awk -f" script (not to awk interpreter), it is
         necessary to prepend a list of arguments with -- (two minus signes). In my view, this
         looks badly.  Also such behaviour violates POSIX/SUS "Utility Syntax Guidelines".

         Example:

         awk_program:

             #!/usr/bin/awk -f

             BEGIN {
                for (i=1; i < ARGC; ++i){
                   printf "ARGV [%d]=%s\n", i, ARGV [i]
                }
             }

         Shell session:

             % awk_program --opt1 --opt2
             /usr/bin/awk: unknown option --opt1 ignored

             /usr/bin/awk: unknown option --opt2 ignored

             % awk_program -- --opt1 --opt2
             ARGV [1]=--opt1
             ARGV [2]=--opt2
             %

         In my opinion awk_program script should work like this

             % awk_program --opt1 --opt2
             ARGV [1]=--opt1
             ARGV [2]=--opt2
             %

       3.
         When "#!/usr/bin/awk -f" script handles arguments (options) and wants to read from
         stdin, it is necessary to add /dev/stdin (or `-') as a last argument explicitly.

         Example:

         awk_program:

             #!/usr/bin/awk -f

             BEGIN {
                if (ARGV [1] == "--flag"){
                   flag = 1
                   ARGV [1] = "" # to not read file named "--flag"
                }
             }

             {
                print "flag=" flag " $0=" $0
             }

         Shell session:

             % echo test | awk_program -- --flag
             % echo test | awk_program -- --flag /dev/stdin
             flag=1 $0=test
             %

         Ideally awk_program should work like this

             % echo test | awk_program --flag
             flag=1 $0=test
             %

       4.
         igawk(1) which is shipped with GNU awk can not be used in shebang.  On most (all?)
         UNIXes scripts beginning with

             #!/usr/local/bin/igawk -f

         will not work.

       runawk was created to solve all these problems

OPTIONS

       -d    Turn on a debugging mode.

       -e program
             Specify program. If -e is not specified, the AWK code is read from program_file.

       -f awk_module
             Activate awk_module. This works the same way as

                 #use "awk_module.awk"

             directive in the code. Multiple -f options are allowed.

       -F fs Set the input field separator FS to the regular expression fs.

       -h    Display help information.

       -t    If this option is applied, a temporary directory is created by runawk and path to it
             is passed to awk child process. Temporary directory is created under
             ${RUNAWK_TMPDIR} (if it is set), or ${TMPDIR} (if it is set) or /tmp directory
             otherwise.  If #use "tmpfile.awk" is detected in a program this option is activated
             automatically.

       -T    Set FS to TAB character. This is equivalent to -F'\t'

       -V    Display version information.

       -v var=val
             Assign the value val to the variable var before execution of the program begins.

DETAILS/INTERNALS

   Standalone script
       Under UNIX-like OS-es you can use runawk by beginning your script with

          #!/usr/local/bin/runawk

       line or something like this instead of

          #!/usr/bin/awk -f

       or similar.

   AWK modules
       In order to activate modules you should add them into awk script like this

         #use "module1.awk"
         #use "module2.awk"

       that is the line that specifies module name is treated as a comment line by normal AWK
       interpreter but is processed by runawk especially.

       Unless you run runawk with option -e, #use must begin with column 0, that is no spaces or
       tabs symbols are allowed before it and no symbols are allowed between # and use.

       Also note that AWK modules can also "use" another modules and so forth.  All them are
       collected in a depth-first order and each one is added to the list of awk interpreter
       arguments prepanded with -f option.  That is #use directive is *NOT* similar to #include
       in C programming language, runawk's module code is not inserted into the place of #use.
       Runawk's modules are closer to Perl's "use" command.  In case some module is mentioned
       more than once, only one -f will be added for it, i.e duplications are removed
       automatically.

       Position of #use directive in a source file does matter, i.e.  the earlier module is
       mentioned, the earlier -f will be generated for it.

       Example:

         file prog:
            #!/usr/local/bin/runawk

            #use "A.awk"
            #use "B.awk"
            #use "E.awk"

            PROG code
            ...

         file B.awk:
            #use "A.awk"
            #use "C.awk"
            B code
            ...

         file C.awk:
            #use "A.awk"
            #use "D.awk"

            C code
            ...

         A.awk and D.awk don't contain #use directive

       If you run

         runawk prog file1 file2

       or

         /path/to/prog file1 file2

       the following command

         awk -f A.awk -f D.awk -f C.awk -f B.awk -f E.awk -f prog -- file1 file2

       will actually run.

       You can check this by running

         runawk -d prog file1 file2

   Module search strategy
       Modules are first searched in a directory where main program (or module in which #use
       directive is specified) is placed.  If it is not found there, then AWKPATH environment
       variable is checked. AWKPATH keeps a colon separated list of search directories.  Finally,
       module is searched in system runawk modules directory, by default PREFIX/share/runawk but
       this can be changed at compile time.

       An absolute path to the module can also be specified.

   Program as an argument
       Like some other interpreters runawk can obtain the script from a command line like this

        /path/to/runawk -e '
        #use "alt_assert.awk"

        {
          assert($1 >= 0 && $1 <= 10, "Bad value: " $1)

          # your code below
          ...
        }'

       runawk can also be used for writing oneliners

        runawk -f abs.awk -e 'BEGIN {print abs(-1)}'

   Selecting a preferred AWK interpreter
       For some reason you may prefer one AWK interpreter or another.  The reason may be
       efficiency for a particular task, useful but not standard extensions or enything else.  To
       tell runawk what AWK interpreter to use, one can use #interp directive

         file prog:
            #!/usr/local/bin/runawk

            #use "A.awk"
            #use "B.awk"

            #interp "/usr/pkg/bin/nbawk"

            # your code here
            ...

       Note that #interp directive should also begin with column 0, no spaces are allowed before
       it and between # and interp.

       Sometimes it also makes sense to give users ability to select their preferred AWK
       interpreter without changing the source code. In runawk it is possible using special
       directive #interp-var which sets an environment variable name assignable by user that
       specifies an AWK interpreter.  For example, the following script

         file foobar:
            #!/usr/bin/env runawk

            #interp-var "FOOBAR_AWK"

            BEGIN {
               print "This is a FooBar application"
            }

       can be run as

            env FOOBAR_AWK=mawk foobar

       or just

            foobar

       In the former case mawk will be used as AWK interpreter, in the latter -- the default AWK
       interpreter.

   Using existing modules only
       In UNIX world it is common practise to write configuration files in a programming language
       of the application. That is, if application is written in Bourne shell, configuration
       files for such application are often written in Bourne as well. Using RunAWK one can do
       the same for applications written in AWK. For example, the following code will use
       ~/.foobarrc file if it exists otherwise /etc/foobar.conf will be used if it exists.

         file foobar:
           #!/usr/bin/env runawk

           #safe-use "~/.foobarrc" "/etc/foobar.conf"

           BEGIN {
             print foo, bar, baz
           }

         file ~/.foobarrc:
           BEGIN {
             foo = "foo10"
             bar = "bar20"
             baz = 123
           }

       Of course, #safe-use directive may be used for other purposes as well.  #safe-use
       directive accepts as much modules as you want, but at most one can be included using awk
       option -f, others are silently ignored, also note that modules are analysed from left to
       right. Leading tilde in the module name is replaced with user's home directory.  Another
       example:

         file foobar:
           #!/usr/bin/env runawk

           #use "/usr/share/foobar/default.conf"
           #safe-use "~/.foobarrc" "/etc/foobar.conf"

           your code is here

       Here the default settings are set in /usr/share/foobar/default.conf, and configuration
       files (if any) are used for overriding them.

   Setting environment
       In some cases you may want to run AWK interpreter with a specific environment. For
       example, your script may be oriented to process ASCII text only. In this case you can run
       AWK with LC_CTYPE=C environment and use regexp ranges.

       runawk provides #env directive for this. String inside double quotes is passed to
       putenv(3) libc function.

       Example:

         file prog:
            #!/usr/local/bin/runawk

            #env "LC_ALL=C"

            $1 ~ /^[A-Z]+$/ { # A-Z is valid if LC_CTYPE=C
                print $1
            }

EXIT STATUS

       If AWK interpreter exits normally, runawk exits with its exit status. If AWK interpreter
       was killed by signal, runawk exits with exit status 128+signal.

ENVIRONMENT

       AWKPATH
             Colon separated list of directories where awk modules are searched.

       RUNAWK_AWKPROG
             Sets the path to the AWK interpreter, used by default, i.e. this variable overrides
             the compile-time default.  Note that #interp directive overrides this.

       RUNAWK_KEEPTMP
             If set, temporary files are not deleted.

AUTHOR

       Copyright (c) 2007-2014 Aleksey Cheusov <vle@gmx.net>

BUGS/FEEDBACK

       Please send any comments, questions, bug reports etc. to me by e-mail or register them at
       sourceforge project home.  Feature requests are also welcomed.

HOME

       <http://sourceforge.net/projects/runawk/>

SEE ALSO awk(1)

                                            2016-02-29                                  runawk(1)