bash expr 中的 shell 浮点数
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shell float number in expr
提问by Zenet
I'm trying to get a float number from this :
我正在尝试从中获取浮点数：
totalmark=$(expr $sum / $subjects )
Is this correct?
这样对吗？
回答by ghostdog74
bash doesn't support floats, use awk or bc/dc
bash 不支持浮点数，使用 awk 或 bc/dc
eg awk
例如 awk
totalmark=$(awk 'BEGIN{print $sum / $subjects}')
or bc
或公元前
totalmark=$(echo "scale=2;$sum/$subjects"|bc)
if you have the luxury to use different shells other than bash, try zsh or ksh
如果您有幸使用 bash 以外的不同 shell，请尝试 zsh 或 ksh
$ zsh -c 'echo $((4/1.3))'
3.0769230769230766
$ ksh -c 'echo $((4/1.3))'
3.07692307692307692
回答by Alok Singhal
I don't think bash has floating-point capabilities. You can try:
我不认为 bash 具有浮点功能。你可以试试：
echo "$sum/$subjects" | bc -l
回答by Paused until further notice.
totalmark=$(echo "scale=4;$sum/$subjects"|bc)
By the way, three answers say that Bash doesn't support floating point arithmetic. While that is true, expris an external program (/usr/bin/exprfor me) and it's the one, in particular, in this case which doesn't support floats.
顺便说一句，三个答案都说 Bash 不支持浮点运算。虽然这是真的，但它是expr一个外部程序（/usr/bin/expr对我来说），尤其是在这种情况下，它不支持浮动。
