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Top Forums Shell Programming and Scripting Maintain Scope of the variable in UNIX Post 302661477 by Ygor on Monday 25th of June 2012 09:45:46 AM
Old 06-25-2012
In bash, variables are local to pipes.

Replace
Code:
cat file | while read line
do
   :
done

With
Code:
while read line
do
   :
done < file

This User Gave Thanks to Ygor For This Post:
 

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line(1) 						      General Commands Manual							   line(1)

NAME
line - read one line from user input SYNOPSIS
timeout] DESCRIPTION
copies one line (up to a new-line) from the standard input and writes it on the standard output. It returns an exit code of 1 on EOF and always prints at least a new-line. It is often used within shell files to read from the user's terminal. Options recognizes the following command-line option: Timeout after timeout seconds where timeout is an integer value (if a non-integer value is specified, it is converted to an integer; i.e., rounded down). A blank is required between and the timeout argument. This option is not documented in POSIX and other industry standards, and should not be used in portable applications. EXTERNAL INFLUENCES
International Code Set Support Single- and multi-byte character code sets are supported. EXAMPLES
The following lines in a shell script prompt for a file name and display information about the file: To limit the response time to 10 seconds, use the form: then test for no response. If no response occurs before timeout expires, a default behavior should be provided. WARNINGS
This command is likely to be withdrawn from X/Open standards. Applications using this command might not be portable to other vendors' sys- tems. As an alternative is recommended. SEE ALSO
sh(1), read(2). STANDARDS CONFORMANCE
line(1)
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