With the exception of the Cygwin environment, the ‘|&’ operator and TCP/IP networking (see TCP/IP Networking) are not supported for MS-DOS or MS-Windows. EMX (OS/2 only) does support at least the ‘|&’ operator.
The MS-DOS and MS-Windows versions of gawk search for
program files as described in AWKPATH Variable. However,
semicolons (rather than colons) separate elements in the AWKPATH
variable. If AWKPATH is not set or is empty, then the default
search path for MS-Windows and MS-DOS versions is
".;c:/lib/awk;c:/gnu/lib/awk"
.
The search path for OS/2 (32 bit, EMX) is determined by the prefix directory
(most likely /usr or c:/usr) that has been specified as an option of
the configure script like it is the case for the Unix versions.
If c:/usr is the prefix directory then the default search path contains .
and c:/usr/share/awk.
Additionally, to support binary distributions of gawk for OS/2
systems whose drive ‘c:’ might not support long file names or might not exist
at all, there is a special environment variable. If UNIXROOT specifies
a drive then this specific drive is also searched for program files.
E.g., if UNIXROOT is set to e: the complete default search path is
".;c:/usr/share/awk;e:/usr/share/awk"
.
An sh-like shell (as opposed to command.com under MS-DOS or cmd.exe under MS-Windows or OS/2) may be useful for awk programming. The DJGPP collection of tools includes an MS-DOS port of Bash, and several shells are available for OS/2, including ksh.
Under MS-Windows, OS/2 and MS-DOS, gawk (and many other text programs) silently
translate end-of-line "\r\n"
to "\n"
on input and "\n"
to "\r\n"
on output. A special BINMODE
variable (c.e.)
allows control over these translations and is interpreted as follows:
BINMODE
is "r"
, or one,
then
binary mode is set on read (i.e., no translations on reads).
BINMODE
is "w"
, or two,
then
binary mode is set on write (i.e., no translations on writes).
BINMODE
is "rw"
or "wr"
or three,
binary mode is set for both read and write.
BINMODE=
non-null-string is
the same as ‘BINMODE=3’ (i.e., no translations on
reads or writes). However, gawk issues a warning
message if the string is not one of "rw"
or "wr"
.
The modes for standard input and standard output are set one time
only (after the
command line is read, but before processing any of the awk program).
Setting BINMODE
for standard input or
standard output is accomplished by using an
appropriate ‘-v BINMODE=N’ option on the command line.
BINMODE
is set at the time a file or pipe is opened and cannot be
changed mid-stream.
The name BINMODE
was chosen to match mawk
(see Other Versions).
mawk and gawk handle BINMODE
similarly; however,
mawk adds a ‘-W BINMODE=N’ option and an environment
variable that can set BINMODE
, RS
, and ORS
. The
files binmode[1-3].awk (under gnu/lib/awk in some of the
prepared distributions) have been chosen to match mawk's ‘-W
BINMODE=N’ option. These can be changed or discarded; in particular,
the setting of RS
giving the fewest “surprises” is open to debate.
mawk uses ‘RS = "\r\n"’ if binary mode is set on read, which is
appropriate for files with the MS-DOS-style end-of-line.
To illustrate, the following examples set binary mode on writes for standard
output and other files, and set ORS
as the “usual” MS-DOS-style
end-of-line:
gawk -v BINMODE=2 -v ORS="\r\n" ...
or:
gawk -v BINMODE=w -f binmode2.awk ...
These give the same result as the ‘-W BINMODE=2’ option in
mawk.
The following changes the record separator to "\r\n"
and sets binary
mode on reads, but does not affect the mode on standard input:
gawk -v RS="\r\n" --source "BEGIN { BINMODE = 1 }" ...
or:
gawk -f binmode1.awk ...
With proper quoting, in the first example the setting of RS
can be
moved into the BEGIN
rule.