36 lines
686 B
Bash
36 lines
686 B
Bash
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#!/bin/bash
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#
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# An IP address looks like this:
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# 192.168.0.5
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# Four groups of 1-3 numbers in the range 0..255 separated by dots.
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#
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re='^([0-9]{1,3}\.){3}[0-9]{1,3}$'
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#
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# The address is expected as the only argument
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#
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if [[ $# -ne 1 ]]; then
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echo "Usage: $0 IP_address"
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exit 1
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fi
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#
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# Validate against the regex
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#
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if [[ $1 =~ $re ]]; then
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#
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# Look at the components and check they are all in range
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#
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for d in ${1//./ }; do
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if [[ $d -lt 0 || $d -gt 255 ]]; then
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echo "$1 is not a valid IP address (contains $d)"
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exit 1
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fi
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done
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echo "$1 is a valid IP address"
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else
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echo "$1 is not a valid IP address"
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fi
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