bash diff commnad 不工作“'diff' 后缺少操作数”
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diff commnad not working "missing operand after `diff'"
提问by ranjith
In diff command am getting following error. Kindly assist how can I specify I want to see difference in two files:
在 diff 命令中出现以下错误。请协助我如何指定我想查看两个文件的差异：
#current_unavail=ranjith
root@iitmserver1 tmp]# cat /tmp/ran
ranjith
[root@iitmserver1 tmp]#
#test=$(cat /tmp/ran)
[root@iitmserver1 tmp]# diff `$current_unavail` `$test`
diff: missing operand after `diff'
diff: Try `diff --help' for more information.
[root@iitmserver1 tmp]#
回答by Sammitch
difftakes two filenamesas arguments, where you appear to be passing in file contentsas the first argument. You will want to change your script/commands to look more like:
diff将两个文件名作为参数，您似乎将文件内容作为第一个参数传递。您需要将脚本/命令更改为更像：
current_unavail=/tmp/unavail_cn.out
result=$(diff $current_unavail /moes/home/pharthiphan/scripts/monitoring/unavail_cn/$last_unavail)
Alternatively, you can use Process Substitutionto pass the output of a command into another command that is expecting a file. eg:
或者，您可以使用进程替换将命令的输出传递到另一个需要文件的命令中。例如：
diff <(echo -e "foo\nbar") <(echo -e "foo\nbaz")
However, while good to know about, this would seem to be a needless level of complexity for your current problem.
然而，虽然很高兴知道，但对于您当前的问题来说，这似乎是不必要的复杂程度。
