shell Trap命令用法

[root@localhost prog]# cat trap2.sh
#!/bin/bash

function cleanup()
{
        echo "Received signals and cleanup files"
}

#trap 到SIG信号，自动停止
trap  ‘cleanup;exit 1‘ SIGHUP
trap  ‘cleanup;exit 1‘ SIGINT

trap  ‘cleanup;exit 1‘ SIGTRAP
#SIGKILL can not be traped
while :
do
        echo "Hi there"
        sleep 1
done
[root@localhost prog]#

[root@localhost prog]# cat trap4.sh
#!/bin/bash

trap ‘cleanup‘ SIGINT
function cleanup()
{
        echo "call function"
        trap - SIGINT    #遇到一次SIGINT， 就会清除掉trap捕捉SIGINT
}
while :
do
        echo "hello aaa"
        sleep 2
done

[root@localhost prog]# cat trap5.sh
#!/bin/bash

cleanup_new()
{
        echo "Some new and extra cleanup performed"
        trap - SIGINT   #第三次TRAP 加exit。消除SIGINT
}

cleanup_old()
{
        echo "Some cleanup performed"
        trap cleanup_new SIGINT    #第二次继续trap INT
}

trap ‘cleanup_old SIGINT‘ SIGINT  #第一次trap SIGINT

while true
do
        echo ‘hello‘
        sleep 1
done
[root@localhost prog]#