SH: save awk command output in variables

Question

I have following code that prints

Disk Usage: 78/223GB (35%)
CPU Load: 2.00
Memory Usage: 5650/16302MB(34.66)

But I want to use out as variables in bah script insated of printing them. How can i do that ?

What I want:

#!/bin/sh

# I want 3 variables which have values from awk 
# How can i convert awk command below to do that ?
$disk_usage
$CPU_usage
$Memory_usage

CODE:

awk 'BEGIN {
    while("df -hP " | getline) {
        if ( $NF == "/" ) {
            printf "Disk Usage: %d/%dGB (%s)\n", $3,$2,$5
        }
    }
    while( getline  < "/proc/loadavg" ) {
        printf "CPU Load: %.2f\n", $(NF-2)
    }

    while( "free -m"| getline) {
        if( $0 ~ /Mem:/) {
        printf "Memory Usage: %s/%sMB (%.2f%)\n", $3,$2,$3*100/$2
        }
    }
}'

Jetchisel · Accepted Answer · 2020-05-03 10:31:02Z

3

with bash

#!/usr/bin/env bash

disk=
cpu_usage=
memory_usage=

while true; do
  read -r disk
  read -r cpu_usage
  read -r memory_usage
  break
done < <(awk -f tst.awk)

printf '%s\n' "$disk" "$cpu_usage" "$memory_usage"

where tst.awk

BEGIN {
    while("df -hP " | getline) {
       if ( $NF == "/" ) {
          printf "Disk Usage: %d/%dGB (%s)\n", $3,$2,$5
       }
    }
    while( getline  < "/proc/loadavg" ) {
       printf "CPU Load: %.2f\n", $(NF-2)
    }

    while( "free -m"| getline) {
      if( $0 ~ /Mem:/) {
       printf "Memory Usage: %s/%sMB (%.2f%)\n", $3,$2,$3*100/$2
       }
    }
}

Instead of a separate script for awk, one can add the awk code inside the Process substitution.

done < <(awk 'BEGIN {
    while("df -hP " | getline) {
       if ( $NF == "/" ) {
       printf "Disk Usage: %d/%dGB (%s)\n", $3,$2,$5
       }
    }
    while( getline  < "/proc/loadavg" ) {
       printf "CPU Load: %.2f\n", $(NF-2)
    }

    while( "free -m"| getline) {
       if( $0 ~ /Mem:/) {
       printf "Memory Usage: %s/%sMB (%.2f%)\n", $3,$2,$3*100/$2
       }
    }
  }'
)

Without the while loop, using { } for command grouping.


{
  read -r disk_usage
  read -r cpu_usage
  read -r memory_usage
} < <( awk 'BEGIN {
  while("df -hP " | getline) {
   if ( $NF == "/" ) {
      printf "Disk Usage: %d/%dGB (%s)\n", $3,$2,$5
    }
  }
   while( getline  < "/proc/loadavg" ) {
     printf "CPU Load: %.2f\n", $(NF-2)
  }
  while( "free -m"| getline) {
     if( $0 ~ /Mem:/) {
       printf "Memory Usage: %s/%sMB (%.2f%)\n", $3,$2,$3*100/$2
     }
   }
  }'
)

printf '%s\n' "$disk_usage" "$cpu_usage" "$memory_usage"

edited May 3, 2020 at 10:31

answered May 3, 2020 at 10:12

Jetchisel

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3 Comments

django Over a year ago

Thankx. What i wanted. Can I make it a single .sh file insated of separate tst.awk

Jetchisel Over a year ago

Yes, You can embed the awk code inside the Process substitution.

django Over a year ago

I seem to have issue embeeding it. can you share how ?

RavinderSingh13 · Accepted Answer · 2020-05-03 10:35:55Z

2

Could you please try following, rather than using bash commands(multiple commands) in single awk you could make it easy by making their different sections of commands like:

cat script.bash
#!/bin/bash
FILESYSTEM="/"
##For disk space
DISK_USAGE=$(df -hP "$FILESYSTEM" | awk '{printf("Disk Usage: %s %s\n",$3,$2,$5)}')
##For Cpur
CPU_DETAILS=$(awk '{printf "CPU Load: %.2f\n", $(NF-2)}' /proc/loadavg)
##For Memory
MEMORY_DETAILS=$(free -m | awk '/Mem/{printf("Memory Usage: %s/%sMB (%.2f%)\n", $3,$2,$3*100/$2)}')

edited May 3, 2020 at 10:35

answered May 3, 2020 at 10:19

RavinderSingh13

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Comments

Guido · Accepted Answer · 2020-05-03 10:22:13Z

1

This will define 3 variables and print to screen:

#!/bin/bash

DISK_USAGE=$(awk 'BEGIN {
    while("df -hP " | getline) {
        if ( $NF == "/" ) {
            printf "Disk Usage: %d/%dGB (%s)\n", $3,$2,$5
        }
    }
}')

CPU_LOAD=$(awk 'BEGIN {
    while( getline  < "/proc/loadavg" ) {
        printf "CPU Load: %.2f\n", $(NF-2)
    }
}')

MEMORY_USAGE=$(awk 'BEGIN {
    while( "free -m"| getline) {
        if( $0 ~ /Mem:/) {
        printf "Memory Usage: %s/%sMB (%.2f%)\n", $3,$2,$3*100/$2
        }
    }
}')

echo $DISK_USAGE
echo $CPU_LOAD
echo $MEMORY_USAGE

answered May 3, 2020 at 10:22

Guido

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