從使用讀取和陷阱的bash腳本中清除退出

Question

運行以下腳本
按Ctrl + C
觀察當前終端行爲。
按下輸入次數並嘗試執行一些命令。

#!/bin/bash 
LOCK_FILE=/tmp/lockfile 
clean_up(){ 
    # Perform program exit housekeeping 
    echo -e "Signal Trapped, exiting..." 
    # Do some Special operation 
    rm -f $LOCK_FILE 
    # 
    exit 1 
} 

touch LOCK_FILE 
trap clean_up SIGHUP SIGINT SIGTERM 
read -s -p "Password: " var 
echo -e "\n Input Password is: $var\n" 

我想知道我在做什麼錯誤？
我嘗試做一個乾淨的退出。 它正在工作，但出口終端STDIN消失後。

Answer 1

read -s如果你在ctrl-c之外，禁用本地回聲（根據文檔），它將無法重置本地回聲的終端模式。比較中斷讀取前後stty -a的輸出以查看所做更改（查看echo*模式）。

您可以使用reset（按照Plutox的評論）或手動重新啓用本地回聲模式來「解決」問題。

$ stty -a 
speed 38400 baud; rows 46; columns 80; line = 0; 
intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = <undef>; 
eol2 = <undef>; swtch = <undef>; start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R; 
werase = ^W; lnext = ^V; flush = ^O; min = 1; time = 0; 
-parenb -parodd cs8 -hupcl -cstopb cread -clocal -crtscts -cdtrdsr 
-ignbrk brkint ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl ixon -ixoff 
-iuclc -ixany imaxbel -iutf8 
opost -olcuc -ocrnl onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0 
isig icanon iexten echo echoe echok -echonl -noflsh -xcase -tostop -echoprt 
echoctl echoke 
$ 
$ cat t.sh 
#!/bin/bash 
clean_up(){ 
    # Perform program exit housekeeping 
    echo -e "Signal Trapped, exiting..." 
    # Do some Special operation 
    rm -f $LOCK_FILE 
    # 
    exit 1 
} 

trap clean_up SIGHUP SIGINT SIGTERM 
read -s -p "Password: " var 
echo -e "\n Input Password is: $var\n" 
$ 
$ sh t.sh 
Password: Signal Trapped, exiting... 
# I ran `stty -a` here but the lack of local echo means it didn't show up. 
$ speed 38400 baud; rows 46; columns 80; line = 0; 
intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = <undef>; 
eol2 = <undef>; swtch = <undef>; start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R; 
werase = ^W; lnext = ^V; flush = ^O; min = 1; time = 0; 
-parenb -parodd cs8 -hupcl -cstopb cread -clocal -crtscts -cdtrdsr 
-ignbrk brkint ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl ixon -ixoff 
-iuclc -ixany imaxbel -iutf8 
opost -olcuc -ocrnl onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0 
isig icanon iexten -echo echoe -echok -echonl -noflsh -xcase -tostop -echoprt 
echoctl echoke