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Echoing command results

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# 8  
Old 10-25-2012
what are you trying to achieve?even without a echo it should work..
# 9  
Old 10-25-2012
Quote:
Originally Posted by msabhi
No just like what rdrtx1 has mentioned...
Tried by removing the brackets from the awk:
Code:
echo (`history 2 | grep -v history | awk 'print $3'`)

and got:
Code:
> cat ios.cfg | ConfProc.sh
/ConfProc.sh: line 14: syntax error near unexpected token ``history 2 | grep -v history | awk 'print $3'`'
/ConfProc.sh: line 14: `echo (`history 2 | grep -v history | awk 'print $3'`)'
>

===========================
and removing the para's from the statement
Code:
echo `history 2 | grep -v history | awk '{print $3}'`

and got
Code:
> cat ios.cfg | ConfProc.sh


You have ended the program
Good bye

>

# 10  
Old 10-25-2012
Please try:-

Code:
echo "`history | tail -2 | head -1 |  grep -v history | awk ' { print $3 } '`"

And for variable assignment try:-

Code:
FILENM=$(echo "`history | tail -2 | head -1 | grep -v history | awk ' { print $3 } '`")

Last edited by Yoda; 10-25-2012 at 04:45 PM..
# 11  
Old 10-25-2012
Quote:
Originally Posted by spacebar
Just run the line like this in your shell script:
Code:
history 2 | grep -v history | awk '{print $3}'

I tried that early on and got no output form the command where, on the command line, I get:
> cat ios.cfg | ConfProc.sh > history 2 | grep -v history | awk '{print $3}' ios.cfg

---------- Post updated at 02:41 PM ---------- Previous update was at 02:39 PM ----------

Quote:
Originally Posted by Marc G
I tried that early on and got no output form the command where, on the command line, I get:
> cat ios.cfg | ConfProc.sh > history 2 | grep -v history | awk '{print $3}' ios.cfg

I even tried using a variable:
FILENM=(history 2 | grep -v history | awk '{print $3}')
echo $FILENM

---------- Post updated at 02:42 PM ---------- Previous update was at 02:41 PM ----------

Quote:
Originally Posted by bipinajith
Please try:-

Code:
echo "`history 2 | grep -v history | awk ' { print $3 } '`"

same results:
Code:
> cat ios.cfg | ConfProc.sh


You have ended the program
Good bye

>

---------- Post updated at 02:45 PM ---------- Previous update was at 02:42 PM ----------

Quote:
Originally Posted by bipinajith
Please try:-

Code:
echo "`history 2 | grep -v history | awk ' { print $3 } '`"

And for variable assignment try:-

Code:
FILENM=$(echo "`history 2 | grep -v history | awk ' { print $3 } '`")

when I get rid of the graves quotes,
Code:
FILENM=$(echo "history 2 | grep -v history | awk ' { print $3 } '")

It actually prints the command out
Code:
> cat ios.cfg | ConfProc.sh
history 2 | grep -v history | awk '{ print  }'

You have ended the program
Good bye

>

---------- Post updated at 02:49 PM ---------- Previous update was at 02:45 PM ----------

sorry,

getting myself confused.

When I get rid of the graves quotes, it looks like this:

Code:
echo "history 2 | grep -v history | awk '{ print $3 }'"

and I get:

Code:
> cat ios.cfg | ConfProc.sh
history 2 | grep -v history | awk ' { print  } '

You have ended the program
Good bye

>

# 12  
Old 10-25-2012
No you have to use the backticks or $(..) at any cost
Code:
`history 2 | grep -v history | awk '{ print $3 }'`

The above command line should give output..But it isn't! its not because you are using it wrongly..but your logic is going wrong..why do you want to print column 3?what it has?
# 13  
Old 10-25-2012
Quote:
Originally Posted by bipinajith
Please try:-

Code:
echo "`history | tail -2 | head -1 |  grep -v history | awk ' { print $3 } '`"

And for variable assignment try:-

Code:
FILENM=$(echo "`history | tail -2 | head -1 | grep -v history | awk ' { print $3 } '`")

Results:
Option 1:
echo "`history 2 | grep -v history | awk ' { print $3 } '`"

yields:
Code:
> cat ios.cfg | ConfProc.sh


You have ended the program
Good bye

>

Option 2:
Code:
FILENM=$(echo "`history | tail -2 | head -1 | grep -v history | awk ' { print $3 } '`")
echo $FILENM

yields:
Code:
> cat ios.cfg | ConfProc.sh


You have ended the program
Good bye

>

---------- Post updated at 03:00 PM ---------- Previous update was at 02:56 PM ----------

Quote:
Originally Posted by msabhi
No you have to use the backticks or $(..) at any cost
Code:
`history 2 | grep -v history | awk '{ print $3 }'`

The above command line should give output..But it isn't! its not because you are using it wrongly..but your logic is going wrong..why do you want to print column 3?what it has?
when I cat a file, column three has the name of that file

Can you write out what you mean when you say I have to use back ticks?
Is that with an echo? in a variable assignment? or on the script line

because i tried it as a script line(by itself) and as an echo and that failed
# 14  
Old 10-25-2012
The reason you aren't getting any o/p from history command(though used properly) is, "history" is disabled when used inside the shell scripts...

---------- Post updated at 04:17 PM ---------- Previous update was at 04:11 PM ----------

Code:
HISTFILE=~/.bash_history
set -o history
echo `history 2 | grep -v history | awk '{print $3}'`

Include as above...This should work...
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