Simple shell script query

sachinh · 09-06-2005, 07:47 AM

Hi GuRU's ,

Got a simple query . I'm using Linux AS 2.1 os . Want to capture current memory utilisation ( used , free and used-swap ) into different variables in the shell script . So that based on these variable values I can execute some commands . Please guide .

bigearsbilly · 09-06-2005, 07:51 AM

do

Code:

set --  `command`

and whatever the output is will populate $1 $2 $3 ... etc.

theYinYeti · 09-06-2005, 10:03 AM

or read:

Code:

read a b c d ... < <(command)

Yves.

bigearsbilly · 09-06-2005, 10:15 AM

typo yeti?

theYinYeti · 09-06-2005, 12:07 PM

No no

Let's assume you want to read the 3 fields returned by command command, then you'd write:

Code:

read field1 field2 field3 < <(command)

The first '<' is to say: `read`'s input should be the said file instead of standard input.
The second '<' is actually '<( ... )' and is a clever trick of bash programming, by which the result of a command is seen as a file: this is called "process substitution".

And even better, you can input your fields in an array!

Code:

read -a fields < <(command)

Yves.

bigearsbilly · 09-07-2005, 04:02 AM

Aah!

I've learnt something new!