脚本的变量??

wllhc

#vi auto.sh
*******************************************************
#!/bin/bash
test1=${1-happyl}
echo 'this is $test1:'$test1
echo 'this is $test1:'$t '$1:'$1
testp=${p=happyp}
echo 'this is $testp:'$testp
echo 'this is $testp:'$p
tests=${3?=fs}
echo 'this is $tests:'$tests '$3:'$3
testb=${b+happyb}
echo 'this is $testb:'$testb'$4:'$4
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#. auto.sh
********************************************************
this is $test1:happyl
this is $test1: $1:
this is $testp:happyp
this is $testp:happyp
bash: 3: =fs
this is $tests: $3:
this is $testb4:
********************************************************
Why???

wacow

你的在我这儿运行结果不一样!
this is $test1:
this is $test1: $1:
this is $testp:happyp
this is $testp:happyp
./auto.sh: line 7: 3: =fs

wllhc

tests=${3?=fs}
在这一行里的？不是说如果给3附值之后就退出了吗？为什么还会继续进行4，5行？

yongjian

个人认为这种写法不正确. 如果判断是否有值, 应是${var?msg}. 如果是附值, ${var=default}. ${3?=fs}的结果应是给出"=fs"的error mesg如果$3为null, 所以我不认为bash会"给3附值之后就退出".