bash 脚本抱怨文件名太长
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bash script complains about file name too long
提问by Jerry Skidmore
So I have a script that does this (jq is a command line JSON processor):
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 $LB_STATUS | jq '.loadBalancer.nodes[] .id'
The output of the last line is:
最后一行的输出是：
1
2
3
But when I try and assign it to an array:
但是当我尝试将它分配给一个数组时：
echo "Creating an Array"
nodeIdArray=($($LB_STATUS | jq '.loadBalancer.nodes[] .id'))
I get this error:
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' produces a few numbers while trying to assign those numbers to an array doesn't work
所以 $LB_STATUS | jq '.loadBalancer.nodes[] .id' 在尝试将这些数字分配给数组时会产生一些数字不起作用
回答by Charles Duffy
What Went Wrong
什么地方出了错
$variable | somethingdoesn't pass the text in variableas input to something-- instead, it runs the contents of $variableas a command. Presumably you wanted echo "$variable" | somethinginstead (but see below!)
$variable | something不会将文本variable作为输入传递给something-- 而是将其内容$variable作为命令运行。大概你想要echo "$variable" | something（但见下文！）
Even if that were fixed, the array=( $(some-command) )idiom is itself buggy. See BashPitfalls #50describing why it shouldn't be used, and the various alternatives.
即使修复了，这个array=( $(some-command) )习语本身也是有问题的。请参阅BashPitfalls #50描述为什么不应该使用它，以及各种替代方案。
What To Do Instead
该怎么做
When feeding content from a variable as an input to a command, it's idiomatic to use a herestring: somecommand <<<"$variable". These aren't free (as they create temporary files), but they're cheaper than pipelines (which fork off subshells).
当将变量中的内容作为命令的输入提供时，使用 herestring: 是惯用的做法somecommand <<<"$variable"。这些不是免费的（因为它们会创建临时文件），但它们比管道（分叉子外壳）便宜。
If you have bash 4.x or newer, you have readarray:
如果你有 bash 4.x 或更新版本，你有readarray：
readarray -t nodeIdArray < <(jq -r '.loadBalancer.nodes[].id' <<<"$LB_STATUS")
If you need compatibility with bash 3.x, read -acan do the job:
如果您需要与 bash 3.x 兼容，read -a可以完成以下工作：
IFS=$'\n' read -r -d '' -a nodeIdArray \
< <(jq -r '.loadBalancer.nodes[].id' <<<"$LB_STATUS" && printf 'nodeIdArray=($($LB_STATUS | jq '.loadBalancer.nodes[] .id'))
')
...which also has the advantage of causing readto return a nonzero exit status if the jqcommand fails.
...read如果jq命令失败，它还具有导致返回非零退出状态的优点。
回答by Hyman
You left out the echo.
你遗漏了echo.
Change
改变
nodeIdArray=($( echo $LB_STATUS | jq '.loadBalancer.nodes[] .id' ))
to
到
##代码##