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Full Discussion: How to read the output of a command line by line and pass it as a variable?
Top Forums Shell Programming and Scripting How to read the output of a command line by line and pass it as a variable? Post 303004112 by bakunin on Tuesday 26th of September 2017 05:06:10 PM
Old 09-26-2017
""
Quote:
Originally Posted by Samah
I tried using while loop with no luck and unsure what exactly is missing in my code.
I would perhaps be able to tell you that, provided i could see it. As it is my crystal ball is currently in repair and i cannot see the code on your computer from here.

I can still tell you how to write a while-loop, though, because it should provide exactly what you want:

Code:
....
InFile="/path/to/your/inputfile"
line=""

while read line ; do
     echo "the line read: $line"
done < "$InFile"

This will read the content of the (text-)file "/path/to/your/inputfile" and output it line by line with a prefixed text of "the line read: ". The content of the line in question is in the variable "line" which you can use to base your own code on.

Notice that this will fail if the file is DOS-style formatted (that is, has CR/LF-line separators instead of the UNIX-style newline characters).

If the file contains things you want to filter out before processing it (like i.e. shell-style comments) you can use a filter to pipe into the while-loop like this (replace "<b>" and "<t>" with literal blank/tab characters, the sed-command removes leading/trailing whitespace, comments and empty lines):
Code:
....
InFile="/path/to/your/inputfile"
line=""

sed 's/#.*//;s/^[<b><t>]*//;s[<b><t>]*$//;/^$/d' "$InFile" |\
while read line ; do
     echo "the line read: $line"
done

I hope this helps.

bakunin
 

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LEARN ABOUT OSF1

pseudo

pseudo(1)						      General Commands Manual							 pseudo(1)

NAME

       pseudo - Starts a non-STREAMS pty interface for a STREAMS device

SYNOPSIS

       pseudo [-l] [-shell shell]

OPTIONS

       Starts  a shell process as the login shell. By default, the command starts this process as an interactive shell.  Specifies the shell to be
       started.  By default, the command starts the shell set by the SHELL environment variable.

DESCRIPTION

       The pseudo command provides an appropriate interface for STREAMS tty devices that are installed on  systems  configured	to  use  the  non-
       STREAMS pty driver.

       The  pseudo  command  opens a pair of master and slave pty devices, and starts a shell process. The command's options allow you to override
       the default shell specification and to specify that the process be started as a login shell.

NOTES

       The pseudo command is available only when one or more of the Tru64 UNIX optional subsets with worldwide support software are  installed	on
       your system.

       In  order  for the pseudo command to provide a non-STREAMS pty interface for STREAMS devices, the system must be configured to use the non-
       STREAMS pty driver. If the system is configured to use the STREAMS pty driver, the command provides a STREAMS pty interface.

SEE ALSO

       Commands:  stty(1)

       Interfaces:  pty(7)

																	 pseudo(1)
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