Question

所以我有一个执行此操作的脚本（jq是命令行JSON处理器）：

echo "Getting LB Node IDs"
echo $LB_STATUS | jq '.loadBalancer.nodes[] .id'

最后一行的输出是：

1
2
3

但是当我尝试将它分配给一个数组时：

echo "Creating an Array"
nodeIdArray=($($LB_STATUS | jq '.loadBalancer.nodes[] .id'))

我收到此错误：

./myShellScript.sh: line 53: {"loadBalancer":{"name":"lbName","id":1,"protocol":"HTTP","port":80,"algorithm":"WEIGHTED_LEAST_CONNECTIONS","status":"ACTIVE","cluster":{"name":"ztm-n22.dfw1.lbaas.rackspace.net"},"nodes":[{"address":"1.2.3.4","id":1,"type":"PRIMARY","port":80,"status":"ONLINE","condition":"ENABLED","weight":1},{"address":"1.2.3.4","id":2,"type":"PRIMARY","port":80,"status":"ONLINE","condition":"ENABLED","weight":1},{"address":"1.2.3.4","id":3,"type":"PRIMARY","port":80,"status":"ONLINE","condition":"ENABLED","weight":1}],"timeout":30,"created":{"time":"2016-06-28T22:14:24Z"},"healthMonitor":{"type":"CONNECT","delay":10,"timeout":5,"attemptsBeforeDeactivation":2},"sslTermination":...<A BOAT LOAD MORE JSON I CUT OUT FOR BREVITY'S SAKE>: File name too long

SO $ LB_STATUS | jq'.loadBalancer.nodes [] .id'在尝试将这些数字分配给数组时产生一些数字不起作用

Answer 1

什么是错的

$variable | something未将variable中的文字作为something的输入传递 - 相反，它会将$variable 的内容作为命令运行。大概你想要echo "$variable" | something代替（但见下文！）

即使修复了问题，array=( $(some-command) )成语本身就是错误的。请参阅BashPitfalls #50，说明不应该使用它的原因，以及各种替代方案。

做什么

当从变量中提供内容作为命令的输入时，使用herestring：somecommand <<<"$variable"是惯用的。这些不是免费的（因为它们创建了临时文件），但它们比管道便宜（它可以分解子套）。

如果你有b或4.x或更新，你有readarray：

readarray -t nodeIdArray < <(jq -r '.loadBalancer.nodes[].id' <<<"$LB_STATUS")

如果您需要与bash 3.x兼容，read -a可以完成这项工作：

IFS=$'\n' read -r -d '' -a nodeIdArray \
  < <(jq -r '.loadBalancer.nodes[].id' <<<"$LB_STATUS" && printf '\0')

...如果read命令失败，它还具有导致jq返回非零退出状态的优势。

Answer 2

您遗漏了echo。

更改

nodeIdArray=($($LB_STATUS | jq '.loadBalancer.nodes[] .id'))

到

nodeIdArray=($( echo $LB_STATUS | jq '.loadBalancer.nodes[] .id' ))

bash脚本抱怨文件名太长

2 个答案:

什么是错的

做什么