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如何检测“while read-t TIMEOUT”循环因超时而退出?

bash

2

Fravadona · 技术社区 · 1 年前

如何检测a while read -t TIMEOUT 循环因超时而退出?

例如:

#!/bin/bash

{
    echo # first line
    sleep 2
    echo # last line
} | {
    while read -t 1; do :; done
    echo 'Did it time out or did it reach eof?'
}

2 回复 | 直到 1 年前

1

3

Philippe 1 年前

商场 read 在变量中的状态:

{
    echo # first line
    sleep 2
    echo # last line
} | {
    while read -t 1; ret=$?; test $ret = 0; do :; done
    echo "Did it time out or did it reach eof? ret=$ret"
}

适用于bash 3.2

while unset REPLY; read -t 1; do
    :
done
test -n "${REPLY+x}" && echo end of file || echo timeout

2

1

dawg 1 年前

从Bash帮助文件中读取:

-t timeout  time out and return failure if a complete line of
        input is not read within TIMEOUT seconds.  The value of the
        TMOUT variable is the default timeout.  TIMEOUT may be a
        fractional number.  If TIMEOUT is 0, read returns
        immediately, without trying to read any data, returning
        success only if input is available on the specified
        file descriptor.  The exit status is greater than 128
        if the timeout is exceeded

注: 退出状态大于128 如果超过超时时间

(这是Bash 5.2)

您还可以查看 THIS.