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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 REDHAT

dircolors

DIRCOLORS(1)								FSF							      DIRCOLORS(1)

NAME

       dircolors - color setup for ls

SYNOPSIS

       dircolors [OPTION]... [FILE]

DESCRIPTION

       Output commands to set the LS_COLORS environment variable.

   Determine format of output:
       -b, --sh, --bourne-shell
	      output Bourne shell code to set LS_COLORS

       -c, --csh, --c-shell
	      output C shell code to set LS_COLORS

       -p, --print-database
	      output defaults

       --help display this help and exit

       --version
	      output version information and exit

       If  FILE  is specified, read it to determine which colors to use for which file types and extensions.  Otherwise, a precompiled database is
       used.  For details on the format of these files, run `dircolors --print-database'.

AUTHOR

       Written by H. Peter Anvin.

REPORTING BUGS

       Report bugs to <bug-coreutils@gnu.org>.

COPYRIGHT

       Copyright (C) 2002 Free Software Foundation, Inc.
       This is free software; see the source for copying conditions.  There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICU-
       LAR PURPOSE.

SEE ALSO

       The  full documentation for dircolors is maintained as a Texinfo manual.  If the info and dircolors programs are properly installed at your
       site, the command

	      info dircolors

       should give you access to the complete manual.

dircolors (coreutils) 4.5.3					   February 2003						      DIRCOLORS(1)
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