Other Inherited Files (The GNU Awk User’s Guide)
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5.8.1 Accessing Other Open Files with gawk
Besides the /dev/stdin
, /dev/stdout
, and /dev/stderr
special file names mentioned earlier, gawk
provides syntax for accessing any other inherited open file:
/dev/fd/N
- The file associated with file descriptor
N
. Such a file must be opened by the program initiating theawk
execution (typically the shell). Unless special pains are taken in the shell from whichgawk
is invoked, only descriptors 0, 1, and 2 are available.
The file names /dev/stdin
, /dev/stdout
, and /dev/stderr
are essentially aliases for /dev/fd/0
, /dev/fd/1
, and /dev/fd/2
, respectively. However, those names are more self-explanatory.
Note that using close()
on a file name of the form "/dev/fd/N"
, for file descriptor numbers above two, does actually close the given file descriptor.