bash 从控制台输出中获取最后 n 行
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grab last n lines from console output
提问by Hersheezy
I want to make a shell script that will effectively grab the last n lines from sterr and stin that were outputted to the console. I have a screen session running a process that will restart it if it crashes via a hacky infinite loop:
我想制作一个 shell 脚本，它可以有效地从输出到控制台的 sterr 和 stin 中获取最后 n 行。我有一个屏幕会话运行一个进程，如果它通过一个hacky无限循环崩溃，它将重新启动它：
#!/bin/bash
#This script will be started in a screen session
counter=0
while [ $counter -lt 10 ]; do
./run_some_process;
last_output=#GRAB PREVIOUS OUTPUT FROM CONSOLE HERE AND LOG TO FILE
echo -e "$last_output" >> mylog.txt;
sleep 5; #sleep for a few seconds before restarting
done
What I need is for the 7th line of code to grab the last 10 or so lines from stderr and stdin and append them to a log file
我需要的是第 7 行代码从 stderr 和 stdin 中获取最后 10 行左右并将它们附加到日志文件中
回答by Alberto Zaccagni
./run_some_process 2>&1 | tail -10 >>logfle
tail -10will give you last ten lines, 2>&1redirects stderr to stdout, >>logfleappends to logfile.
tail -10会给你最后十行，2>&1将标准错误重定向到标准输出，>>logfle附加到日志文件。
