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66 lines
962 B
66 lines
962 B
#!/usr/bin/env bash |
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# Unofficial Bash Strict Mode |
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set -euo pipefail |
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IFS=' |
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' |
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number='^-?[0-9]+$' |
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do_add () { |
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echo $(($1 + $2)) |
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} |
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do_sub () { |
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echo $(($1 - $2)) |
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} |
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do_mult () { |
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echo $(($1 * $2)) |
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} |
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do_divide () { |
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echo $(($1 / $2)) |
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} |
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if [ $# != 3 ] |
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then |
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>&2 echo "Error: expect 3 arguments" |
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exit 1 |
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elif ! [[ $1 =~ $number && $3 =~ $number ]] |
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then |
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>&2 echo "Error: invalid number" |
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exit 4 |
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else |
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case $2 in |
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"+") |
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echo $(do_add $1 $3) |
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;; |
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"-") |
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echo $(do_sub $1 $3) |
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;; |
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"*") |
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echo $(do_mult $1 $3) |
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;; |
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"/") |
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if [ $3 == 0 ] |
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then |
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>&2 echo "Error: division by 0" |
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exit 2 |
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fi |
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echo $(do_divide $1 $3) |
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;; |
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*) |
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>&2 echo "Error: invalid operator" |
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exit 3 |
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;; |
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esac |
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fi
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