如何输出重定向返回到显示单个命令

Question

在外壳脚本我有

LOG=/my.log 
exec 1>>$LOG 
exec 2>&1 

被重定向在外壳脚本的输出。现在问题是在下面

LOG=/etc/security/aixpert/log/aixpert.log 
exec 1>>$LOG 
exec 2>&1 

#some codes 

print "I want this on cmd output not in log" 

#I want rest of the output redirected to log as usual 

我该怎么做？

Answer 1

关键是要克隆stdout在将控制台重定向到日志之前将控制台复制到任意fd（我选择了3）。每当你想输出发送到你刚才重定向FD 1控制台回的fd 3 >&3对于一个命令

LOG=/etc/security/aixpert/log/aixpert.log 

exec 3>&1 >>"$LOG" 2>&1 

#some codes 

echo "I want this on cmd output not in log" >&3 

#I want rest of the output redirected to log as usual 

Answer 2

# save stdout as fd 3 
exec 3>&1 
exec 1>>$LOG 
exec 2>&1 

echo foo >&3 # output to old stdout 
echo bar  # output to logfile