Exercises small shell script basis (b)

Exercises small shell script basis (b)

Write a memusage.sh, memory usage is calculated based on the results of the command Free

Ideas:

1: In the screen output "free" to see the results of the command

2: According to the results given that we need to use "total" and "free"

total: column shows the total available system physical memory and swap space.

free: column shows how much physical memory and swap space available for use.

Here we look at Mem (memory usage) can be.

3: We create a script but we just use ( "total" and "free") in free of Mem in how to write, here we have to use "grep (filtered)", the pipe symbol (|) and awk

grep: filtering keywords corresponding to the line, where we look at "Mem"

awk: column unit reads data filtering tools

wherein awk -F (-F) [delimiter is used to specify part is specified, the default separated by a space or tab], here we see the "free" we are not directly delimiter followed by a space on the back awk it.

awk '{prin $ 2}': this is a fixed format columns here that $ 2 for free in the total where you want to use it in a column just behind the "$" write a few numbers. But here we begin to run from the first column is not to be confused with Mem.

4: We started to think about how to use the calculation to show the occupancy rate in the shell can not come out like we used to use handwriting or using a calculator as a direct knock digital computing {(135,276 divided by 1,867,024) multiplied by 100} the outcome does not support fractional arithmetic operations with numerical variable when the shell, I think so can put "free" multiplied by 100 and divided by the "total" is ($ a \ * 100 / $ b)

Because I'm free now changed so that the result is