IO Redirection

B.7 I/O Redirection

Table 2.8 shows a complete list of I/O redirectors. (This table is also included earlier as Table 7.1 .) Note that there are two formats for specifying standard output and error redirection: &>file and >&file . The second of these, and the one used throughout this book, is the preferred way.

Table B.8. I/O Redirectors

Redirector

Function

cmd1 cmd2

Pipe; take standard output of cmd1 as standard input to cmd2

> file

Direct standard output to file

< file

Take standard input from file

>> file

Direct standard output to file ; append to file if it already exists

> file

Force standard output to file even if noclobber is set

n > file

Force output to file from file descriptor n

 

even if noclobber set

<> file

Use file as both standard input and standard output

n <> file

Use file as both input and output for file descriptor n

<< label

Here-document

n > file

Direct file descriptor n to file

n < file

Take file descriptor n from file

>> file

Direct file descriptor n to file ; append to file if it already exists

n >&

Duplicate standard output to file descriptor n

n <&

Duplicate standard input from file descriptor n

n >& m

File descriptor n is made to be a copy of the output file descriptor

n <& m

File descriptor n is made to be a copy of the input file descriptor

&> file

Directs standard output and standard error to file

<&-

Close the standard input

>&-

Close the standard output

n >&-

Close the output from file descriptor n

n <&-

Close the input from file descriptor n

 



Learning the Bash Shell
Learning the bash Shell: Unix Shell Programming (In a Nutshell (OReilly))
ISBN: 0596009658
EAN: 2147483647
Year: 1998
Pages: 104

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