string manipulation issue - Shell Programming and Scripting

illcar · #1 (**permalink**) 11-20-2008

I have myMethod that gives me available,used,free disk space in KB. I parse the used disk space using awk. That gives me something like 830,016. I want the output to be 830016 so that I can add 100000 to it. In other words I would like to use used_space variable in numeric calculations (using expr).

Code:

.....
myMethod
used_space="`myMethod | grep sum | awk -F' ' '{print $3}'`"
echo $used_space
echo ${used_space/,/}

But the last line above gives me error:

Code:

sum                 1,977,920      830,016    1,147,904
830,016
./test.sh: bad substitution

What can I do? If I do the same thing on command line it works fine!

Code:

bash-3.00# export abc=830,123
bash-3.00# echo ${abc/,/}
830123
bash-3.00#

danmero · #2 (**permalink**) 11-20-2008

Quote:

Originally Posted by illcar

Code:

used_space="`myMethod | grep sum | awk -F' ' '{print $3}'`"

Let awk do the job and don't get complicated.

Code:

used_space=`myMethod | awk '/sum/{gsub(/,/,"");print $3}'`

alex_5161 · #3 (**permalink**) 11-20-2008

I guess you havn't specify the shell in script. (Do not remember how that line is named..)
First line in script

Code:

#! /usr/bin/bash

for example.

In bash it works fine, but I have tried it in ksh:

Code:

> ec $used_space
830,016
> ec ${used_space/,/}
ksh: ${used_space/,/}: bad substitution
>

illcar · #4 (**permalink**) 11-21-2008

I am sorry, I am still having issues. I changed the code as follows:

Code:

 
myMethod
used=`myMethod | awk '{gsub(/,/,""); print $3}'`
echo $used

Now I get a different error. If it is not clear what could be wrong, any pointers for debugging awk would be appreciated.

Code:

 
bash-3.00# ./test.sh 
sum                 1,977,920      795,648    1,182,272
awk: syntax error near line 1
awk: illegal statement near line 1
bash-3.00# stty: : I/O error

The first line of the script is:

Code:

 
#!/bin/sh

alex_5161 · #5 (**permalink**) 11-21-2008

problem is:
1: 'awk' does not know the function 'gsub()'
use 'nawk'
2: why you do not change the 'sh' to 'bash' - everything will be simpler

illcar · #6 (**permalink**) 11-24-2008

Quote:

Originally Posted by alex_5161

problem is:
1: 'awk' does not know the function 'gsub()'
use 'nawk'
2: why you do not change the 'sh' to 'bash' - everything will be simpler

Thanks, nawk did the trick.

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