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Full Discussion: Question on bash redirection
Top Forums UNIX for Beginners Questions & Answers Question on bash redirection Post 303035997 by MadeInGermany on Wednesday 12th of June 2019 01:51:45 AM
Old 06-12-2019
x < y means: run command x and feed its input (stdin) from file y.
It is true that file y is opened for reading before command x runs.
diff <(sort testfile.txt) <(sort testfile2.txt) means: open a device ("/dev/fd/..."), run sort and redirect its output to the device, open another device, run another sort and redirect its output, run diff with the two devices as arguments (that diff treats as input filenames).
Quote:
man bash
...
Process substitution
...
The process list is run asynchronously, and its input or output appears as a filename. This filename is passed as an argument to the current command as the result of the expansion. If the >(list) form is used, writing to the file will provide input for list. If the <(list) form is used, the file passed as an argument should be read to obtain the output of list. Note that no space may appear between the < or > and the left parenthesis, otherwise the construct would be interpreted as a redirection. Process substitution is supported on systems that support named pipes (FIFOs) or the /dev/fd method of naming open files.
...
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LEARN ABOUT XFREE86

git-check-attr

GIT-CHECK-ATTR(1)						    Git Manual							 GIT-CHECK-ATTR(1)

NAME

       git-check-attr - Display gitattributes information

SYNOPSIS

       git check-attr [-a | --all | attr...] [--] pathname...
       git check-attr --stdin [-z] [-a | --all | attr...]

DESCRIPTION

       For every pathname, this command will list if each attribute is unspecified, set, or unset as a gitattribute on that pathname.

OPTIONS

       -a, --all
	   List all attributes that are associated with the specified paths. If this option is used, then unspecified attributes will not be
	   included in the output.

       --cached
	   Consider .gitattributes in the index only, ignoring the working tree.

       --stdin
	   Read pathnames from the standard input, one per line, instead of from the command-line.

       -z
	   The output format is modified to be machine-parseable. If --stdin is also given, input paths are separated with a NUL character instead
	   of a linefeed character.

       --
	   Interpret all preceding arguments as attributes and all following arguments as path names.

       If none of --stdin, --all, or -- is used, the first argument will be treated as an attribute and the rest of the arguments as pathnames.

OUTPUT

       The output is of the form: <path> COLON SP <attribute> COLON SP <info> LF

       unless -z is in effect, in which case NUL is used as delimiter: <path> NUL <attribute> NUL <info> NUL

       <path> is the path of a file being queried, <attribute> is an attribute being queried and <info> can be either:

       unspecified
	   when the attribute is not defined for the path.

       unset
	   when the attribute is defined as false.

       set
	   when the attribute is defined as true.

       <value>
	   when a value has been assigned to the attribute.

       Buffering happens as documented under the GIT_FLUSH option in git(1). The caller is responsible for avoiding deadlocks caused by
       overfilling an input buffer or reading from an empty output buffer.

EXAMPLES

       In the examples, the following .gitattributes file is used:

	   *.java diff=java -crlf myAttr
	   NoMyAttr.java !myAttr
	   README caveat=unspecified

       o   Listing a single attribute:

	   $ git check-attr diff org/example/MyClass.java
	   org/example/MyClass.java: diff: java

       o   Listing multiple attributes for a file:

	   $ git check-attr crlf diff myAttr -- org/example/MyClass.java
	   org/example/MyClass.java: crlf: unset
	   org/example/MyClass.java: diff: java
	   org/example/MyClass.java: myAttr: set

       o   Listing all attributes for a file:

	   $ git check-attr --all -- org/example/MyClass.java
	   org/example/MyClass.java: diff: java
	   org/example/MyClass.java: myAttr: set

       o   Listing an attribute for multiple files:

	   $ git check-attr myAttr -- org/example/MyClass.java org/example/NoMyAttr.java
	   org/example/MyClass.java: myAttr: set
	   org/example/NoMyAttr.java: myAttr: unspecified

       o   Not all values are equally unambiguous:

	   $ git check-attr caveat README
	   README: caveat: unspecified

SEE ALSO

       gitattributes(5).

GIT

       Part of the git(1) suite

Git 2.17.1							    10/05/2018							 GIT-CHECK-ATTR(1)
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