问题描述
此后继错误的尾部语法或grep命令?，但是我正在读取给定条件下的实时日志条目，并在满足条件时继续执行脚本的其余部分.我正在使用这个:
This follows on from Faulty tail syntax or grep command? but I'm reading a live log entries for given conditions and when they're met continuing the execution of the rest of the script. I'm using this:
tail -Fn0 /var/log/messages | grep -q "CPU utilization" | grep -q "exceeded threshold"
FPC=$(echo $line | awk 'END { print substr($8,1,1) }')
PIC=$(echo $line | awk 'END { print substr($11,1,1) }')
echo FPC $FPC
echo PIC $PIC
echo "Running information gathering"...and rest of script.
这对于条件检测和进一步执行非常有效，但是我没有用于测试FPC和PIC变量的日志条目.我试过这样包装尾部语句:
Which works perfectly for the conditions detection and further execution, but I don't have the log entry to test for the FPC and PIC variables. I've tried wrapping the tail statement thus:
line=$(tail -Fn0 /var/log/messages | grep -q "CPU utilization" | grep -q "exceeded threshold")
但是grep -q静默退出，并且$ line变量为空.我已经尝试过:
but grep -q exits silently and the $line variable is blank. I've tried:
line=$(tail -Fn0 /var/log/messages | grep -m1 "CPU utilization" | grep -m1 "exceeded threshold")
，直到我尝试将CONTROL-C移出脚本后，该命令才起作用.然后它可以正常工作，并且可以完美持续.有人可以帮忙吗?
which doesn't work until I attempt to CONTROL-C out of the script. Then it works fine and continues perfectly. Can someone help please?
我稍后在脚本中需要变量FPC和PIC.
I need the variables FPC and PIC later in the script.
推荐答案
假设以后不再需要这些变量，则可以执行以下操作:
Assuming that you don't need these variables later on, you could do something like this:
tail -Fn0 /var/log/messages | \
awk '/CPU utilization/ && /exceeded threshold/ {
print "FPC", substr($8,1,1); print "PIC", substr($11,1,1); exit }'
当该行与两种模式都匹配时，请打印出您感兴趣的两个部分并退出.
When the line matches both patterns, print the two parts of it that you are interested in and exit.
如果确实需要变量，则可以改成这样:
If you do need the variables, you could do something like this instead:
line=$(tail -Fn0 /var/log/messages | awk '/CPU utilization/&&/exceeded threshold/{print;exit}')
FPC=$(echo "$line" | awk '{ print substr($8,1,1) }')
PIC=$(echo "$line" | awk '{ print substr($11,1,1) }')
这篇关于尾巴-Fn0和变量的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！