Gawk accepts the following options. Standard options are listed
first, followed by options for gawk extensions, listed
alphabetically by short option.
-f program-file
--file program-file
Read the AWK program source from the file program-file,
instead of from the first command line argument. Multiple
-f (or --file) options may be used. Files read with -f
are treated as if they begin with an implicit @namespace
"awk" statement.
-F fs
--field-separator fs
Use fs for the input field separator (the value of the FS
predefined variable).
-v var=val
--assign var=val
Assign the value val to the variable var, before execution
of the program begins. Such variable values are available
to the BEGIN rule of an AWK program.
-b
--characters-as-bytes
Treat all input data as single-byte characters. In other
words, don't pay any attention to the locale information
when attempting to process strings as multibyte
characters. The --posix option overrides this one.
-c
--traditional
Run in compatibility mode. In compatibility mode, gawk
behaves identically to Brian Kernighan's awk; none of the
GNU-specific extensions are recognized. See GNU
EXTENSIONS, below, for more information.
-C
--copyright
Print the short version of the GNU copyright information
message on the standard output and exit successfully.
-d[file]
--dump-variables[=file]
Print a sorted list of global variables, their types and
final values to file. If no file is provided, gawk uses a
file named awkvars.out in the current directory.
Having a list of all the global variables is a good way to
look for typographical errors in your programs. You would
also use this option if you have a large program with a
lot of functions, and you want to be sure that your
functions don't inadvertently use global variables that
you meant to be local. (This is a particularly easy
mistake to make with simple variable names like i, j, and
so on.)
-D[file]
--debug[=file]
Enable debugging of AWK programs. By default, the
debugger reads commands interactively from the keyboard
(standard input). The optional file argument specifies a
file with a list of commands for the debugger to execute
non-interactively.
-e program-text
--source program-text
Use program-text as AWK program source code. This option
allows the easy intermixing of library functions (used via
the -f and --include options) with source code entered on
the command line. It is intended primarily for medium to
large AWK programs used in shell scripts. Each argument
supplied via -e is treated as if it begins with an
implicit @namespace "awk" statement.
-E file
--exec file
Similar to -f, however, this is option is the last one
processed. This should be used with #! scripts,
particularly for CGI applications, to avoid passing in
options or source code (!) on the command line from a URL.
This option disables command-line variable assignments.
-g
--gen-pot
Scan and parse the AWK program, and generate a GNU .pot
(Portable Object Template) format file on standard output
with entries for all localizable strings in the program.
The program itself is not executed. See the GNU gettext
distribution for more information on .pot files.
-h
--help Print a relatively short summary of the available options
on the standard output. (Per the GNU Coding Standards,
these options cause an immediate, successful exit.)
-i include-file
--include include-file
Load an awk source library. This searches for the library
using the AWKPATH environment variable. If the initial
search fails, another attempt will be made after appending
the .awk suffix. The file will be loaded only once (i.e.,
duplicates are eliminated), and the code does not
constitute the main program source. Files read with
--include are treated as if they begin with an implicit
@namespace "awk" statement.
-I
--trace
Print the internal byte code names as they are executed
when running the program. The trace is printed to standard
error. Each ``op code'' is preceded by a + sign in the
output.
-l lib
--load lib
Load a gawk extension from the shared library lib. This
searches for the library using the AWKLIBPATH environment
variable. If the initial search fails, another attempt
will be made after appending the default shared library
suffix for the platform. The library initialization
routine is expected to be named dl_load().
-L [value]
--lint[=value]
Provide warnings about constructs that are dubious or non-
portable to other AWK implementations. With an optional
argument of fatal, lint warnings become fatal errors.
This may be drastic, but its use will certainly encourage
the development of cleaner AWK programs. With an optional
argument of invalid, only warnings about things that are
actually invalid are issued. (This is not fully
implemented yet.) With an optional argument of no-ext,
warnings about gawk extensions are disabled.
-M
--bignum
Force arbitrary precision arithmetic on numbers. This
option has no effect if gawk is not compiled to use the
GNU MPFR and GMP libraries. (In such a case, gawk issues
a warning.)
-n
--non-decimal-data
Recognize octal and hexadecimal values in input data. Use
this option with great caution!
-N
--use-lc-numeric
Force gawk to use the locale's decimal point character
when parsing input data. Although the POSIX standard
requires this behavior, and gawk does so when --posix is
in effect, the default is to follow traditional behavior
and use a period as the decimal point, even in locales
where the period is not the decimal point character. This
option overrides the default behavior, without the full
draconian strictness of the --posix option.
-o[file]
--pretty-print[=file]
Output a pretty printed version of the program to file.
If no file is provided, gawk uses a file named awkprof.out
in the current directory. This option implies
--no-optimize.
-O
--optimize
Enable gawk's default optimizations upon the internal
representation of the program. Currently, this just
includes simple constant folding. This option is on by
default.
-p[prof-file]
--profile[=prof-file]
Start a profiling session, and send the profiling data to
prof-file. The default is awkprof.out. The profile
contains execution counts of each statement in the program
in the left margin and function call counts for each user-
defined function. This option implies --no-optimize.
-P
--posix
This turns on compatibility mode, with the following
additional restrictions:
• \x escape sequences are not recognized.
• You cannot continue lines after ? and :.
• The synonym func for the keyword function is not
recognized.
• The operators ** and **= cannot be used in place of
^ and ^=.
-r
--re-interval
Enable the use of interval expressions in regular
expression matching (see Regular Expressions, below).
Interval expressions were not traditionally available in
the AWK language. The POSIX standard added them, to make
awk and egrep consistent with each other. They are
enabled by default, but this option remains for use
together with --traditional.
-s
--no-optimize
Disable gawk's default optimizations upon the internal
representation of the program.
-S
--sandbox
Run gawk in sandbox mode, disabling the system() function,
input redirection with getline, output redirection with
print and printf, and loading dynamic extensions. Command
execution (through pipelines) is also disabled. This
effectively blocks a script from accessing local
resources, except for the files specified on the command
line.
-t
--lint-old
Provide warnings about constructs that are not portable to
the original version of UNIX awk.
-V
--version
Print version information for this particular copy of gawk
on the standard output. This is useful mainly for knowing
if the current copy of gawk on your system is up to date
with respect to whatever the Free Software Foundation is
distributing. This is also useful when reporting bugs.
(Per the GNU Coding Standards, these options cause an
immediate, successful exit.)
-- Signal the end of options. This is useful to allow further
arguments to the AWK program itself to start with a '-'.
This provides consistency with the argument parsing
convention used by most other POSIX programs.
In compatibility mode, any other options are flagged as invalid,
but are otherwise ignored. In normal operation, as long as
program text has been supplied, unknown options are passed on to
the AWK program in the ARGV array for processing. This is
particularly useful for running AWK programs via the #!
executable interpreter mechanism.
For POSIX compatibility, the -W option may be used, followed by
the name of a long option.
