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Top Forums Shell Programming and Scripting Difference between "Command substitution" and "Process substitution" Post 302268287 by Christoph Spohr on Monday 15th of December 2008 10:20:15 AM
Old 12-15-2008
Hi,

$(...) means execute the command ... and print the output
to the command line.
<(...) and =(...) create a temporary file of the output and
redirect the output of this to the command line.

To understand the difference try:

Code:
diff $(ls) $(ls)

and

Code:
diff <(ls) <(ls)

The first will fail as diff expects input from a file.

HTH Chris
 

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getext(1M)																getext(1M)

NAME
getext - get VxFS extent attributes SYNOPSIS
file... DESCRIPTION
displays extent attribute information associated with a set of files. Options recognizes the following options: Do not print the filenames for which extent attributes are displayed. Specify the VxFS file system type. Do not print output for files that do not have fixed extent sizes or reservations. Echo the completed command line, but do not execute the command. The command line is generated by incorporating the user-specified options. This option allows the user to verify the command line. Operands recognizes the following operand: file Name of file in a VxFS file system. Notes Only the and allocation flags (set through setext(1M) or the ioctl) are persistent attributes of the file and therefore visible via or the ioctl. is also visible, although it is cleared and the reservation is reduced on the final close of the file. EXAMPLES
The following example shows a file with a block size of 1024 bytes, 36 blocks reserved, a fixed extent size of 3 blocks, and all extents aligned to 3 block boundaries: The file size cannot be extended once the current reservation is exhausted. Reservations and fixed extent sizes are allocated in units of the file system block size. SEE ALSO
setext(1M), vxfsio(7). getext(1M)
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