64 lines
1.4 KiB
Bash
Executable File
64 lines
1.4 KiB
Bash
Executable File
#!/bin/sh
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if [ "$1" = "-h" ]; then
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cat <<EOF>&2
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Usage: ${0##*/}
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Return the CPU usage. Linux only.
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EOF
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exit
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fi
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if [ ! "$(uname)" = "Linux" ]; then
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echo >&2 "Linux only."
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exit 1
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fi
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## CPU usage
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##
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## A typical CPU array is (on Linux Kernel 3.0)
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## cpu 158150 0 52354 18562746 1472 0 10198 0 0 0
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##
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## The meanings of the columns are as follows, from left to right:
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##
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## user: normal processes executing in user mode
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## nice: niced processes executing in user mode
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## system: processes executing in kernel mode
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## idle: twiddling thumbs
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## iowait: waiting for I/O to complete
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## irq: servicing interrupts
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## softirq: servicing softirqs
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## ... (see 'man 5 proc' for further details)
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##
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## Only the first 4 values are interesting here.
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cpuarray="$(grep '^cpu ' /proc/stat)"
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## We start at field #3 since there are 2 spaces after 'cpu'.
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f1=$(echo "$cpuarray" | cut -f3 -d' ')
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f2=$(echo "$cpuarray" | cut -f4 -d' ')
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f3=$(echo "$cpuarray" | cut -f5 -d' ')
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f4=$(echo "$cpuarray" | cut -f6 -d' ')
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totalA=$((f1+f2+f3+f4))
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idleA=$f4
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sleep 1
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cpuarray="$(grep '^cpu ' /proc/stat)"
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f1=$(echo "$cpuarray" | cut -f3 -d' ')
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f2=$(echo "$cpuarray" | cut -f4 -d' ')
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f3=$(echo "$cpuarray" | cut -f5 -d' ')
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f4=$(echo "$cpuarray" | cut -f6 -d' ')
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totalB=$((f1+f2+f3+f4))
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idleB=$f4
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totaldiff=$((${totalB:-0}-${totalA:-0}))
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if [ $totaldiff -eq 0 ]; then
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echo 0
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else
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echo "$((100 - 100 * (idleB-idleA) / totaldiff))"
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fi
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