bash - 从使用读取和陷阱的 bash 脚本中清除退出

Question

运行下面的脚本
按 Ctrl+C
观察当前的终端行为。
按几次 enter 并尝试执行一些命令。

#!/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"

我想知道我做错了什么？
我尝试做一个干净的退出。它正在工作，但在退出终端后 STDIN 消失。

Answer 1

read -s 禁用本地回显(根据文档)如果您 ctrl-c 从读取中读取它无法重置本地回显的终端模式。比较中断读取前后 stty -a 的输出以查看它所做的更改(查看 echo* 模式)。

您可以使用reset(根据 Plutox 的评论)或手动重新启用本地 echo 模式以“修复”问题。

$ 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