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Top Forums Shell Programming and Scripting Help with UNIX READ command usage.. Post 302767557 by kumarjt on Thursday 7th of February 2013 05:21:14 AM
Old 02-07-2013
Help with UNIX READ command usage..

Tested on : bash
Will be implementing on : ksh

I dont know if this is weird , or my idea of Unix stdin or stdout is completely messed up , but if I use the following command, I am getting a proper output.
Code:
ls -l | head -1 | while read a ; do echo $a ;done

and the output is soemthing like total 32

But, on the contrary , if I use
Code:
ls -l | head -1 | read a ; echo $a

it yields an empty value

My idea was , as because the commands are piped , the output of ls command will flow to standard input and will be read to the variable a.
But , its happening only when I used the while-read loop , and not the stand alone read .

Am I missing something here ? Please help.



Thanks
Kumarjit.

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Last edited by Franklin52; 02-07-2013 at 06:26 AM.. Reason: fixed code tags
 

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times(1)							   User Commands							  times(1)

NAME
times - shell built-in function to report time usages of the current shell SYNOPSIS
sh times ksh times DESCRIPTION
sh Print the accumulated user and system times for processes run from the shell. ksh Print the accumulated user and system times for the shell and for processes run from the shell. On this man page, ksh(1) commands that are preceded by one or two * (asterisks) are treated specially in the following ways: 1. Variable assignment lists preceding the command remain in effect when the command completes. 2. I/O redirections are processed after variable assignments. 3. Errors cause a script that contains them to abort. 4. Words, following a command preceded by ** that are in the format of a variable assignment, are expanded with the same rules as a vari- able assignment. This means that tilde substitution is performed after the = sign and word splitting and file name generation are not performed. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWcsu | +-----------------------------+-----------------------------+ SEE ALSO
ksh(1), sh(1), time(1), attributes(5) SunOS 5.10 15 Apr 1994 times(1)
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