Re: Bash: how do I use a variable as a log file?

[ToddAndMargo]

On 06/07/2014 07:17 PM, ToddAndMargo wrote:
On 06/07/2014 06:00 PM, zxq9 wrote:
On Saturday 07 June 2014 17:38:35 you wrote:
Hi All,
Bash: I am trying to use a variable to hold
a log and add to it as I go.  I can do this
with a temp file, but I'd rather do it with
a variable.

I have gotten this far:

A=$(echo -e  "abc\n")
A="$A"$(echo -e  "def\n")
A="$A"$(echo -e  "ghi\n")

echo $A
abcdefghi

echo -e $A
abcdefghi

What am I doing wrong?  Is it better to just break
down and just use a file?

The assignment doesn't need echo, and the series of "echo -e" is
swallowing
the newlines you expected to have in place.

Here's an example:

-----------------
ceverett@jalapeno ~/Code/bash $ cat var-log.bash
#! /bin/bash
a="start of log"
for newdata in $(seq 1 10)
do
   a="$a\n$newdata"
done
echo -e "$a"

ceverett@jalapeno ~/Code/bash $ ./var-log.bash
start of log
1
2
3
4
5
6
7
8
9
10
-----------------

But really, you shouldn't store a log in a variable, especially if it
might
receive a lot of traffic (and especially since you lose everything in the
event of a program interruption of any sort, which defeats the
purpose). You
could accumulate a bit of data in a variable, but you should always
flush it
to a file. The append redirect operator was designed specifically to
make this
easy; not using it is going against the grain.


Hi zxq9,

    I see what I did wrong.  Thank you!

    It is a small log.  Only about 20 line
of text in it.

-T




Hi Guys,

Thank you for the help.  If you are curious, this is
what became of all the bash syntax questions.

-T


DownloadApp () {
   # $1 Application Name
   # RtnState: 0 = unknown (default)
   #           1 = no update found
   #           2 = update found
   #           3 = error

   App=$1
   Status=0
   Col_Grey="\x1b[30;01m"
   Col_Red="\x1b[31;01m"
   Col_Blue="\x1b[38;49;00m"
   Col_Reset="\x1b[39;49;00m"

   AppDot="${App}:                          "; AppDot="${AppDot:0:30}"


   eval "$App"; RtnState=$?
   if [ "$RtnState" == "3" ]; then MasterStatus=1; fi

   case $RtnState in
      "1" )
           StatusLog="${StatusLog}\n${AppDot} ${Col_Grey}no new 
updates${Col_Reset}"
           ;;

      "2" )
           StatusLog="${StatusLog}\n${AppDot} ${Col_Blue}new update 
downloaded${Col_Reset}"
           ;;

      "3" )
           StatusLog="${StatusLog}\n${AppDot} ${Col_Red}ERROR.  See 
details above${Col_Reset}"
           MasterStatus="1"
           ;;

      *)
           StatusLog="${StatusLog}\n${AppDot} ${Col_Red}did not return 
a recognized status <{$RtnState}>${Col_Reset}"
   esac

   tput sgr0 # Reset text attributes to normal without clear
}