EXPECT 脚本中的正则表达式模式匹配

Question

我有一个 EXPECT 脚本来监视 IBMIHS 服务器上的 http pid：

    ....
    send "ps -ef|grep htt|grep start|wc -l \r"
    expect {
       -re {.*(\d+).*} {

          set theNum $expect_out(1,string)
      }
    }

    puts "theNum = $theNum"

    if {$theNum > 8} {
      puts "it is ok"
    } else {
      puts "it is not ok"
    }
....

send "ps -ef|grep htt|grep start|wc -l \r" 生成：

send: sending "ps -ef|grep htt|grep start|wc -l \r" to { exp5 }
Gate keeper glob pattern for '.(\d+).' is ''. Not usable, disabling the performance booster.

expect: does "" (spawn_id exp5) match regular expression ".(\d+)."? (No Gate, RE only) gate=yes re=no
ps -ef|grep htt|grep start|wc -l

expect: does "ps -ef|grep htt|grep start|wc -l \r\n" (spawn_id exp5) match regular expression ".(\d+)."? (No Gate, RE only) gate=yes re=no
11

expect: does "ps -ef|grep htt|grep start|wc -l \r\n11\r\n" (spawn_id exp5) match regular expression ".(\d+)."? (No Gate, RE only) gate=yes re=yes

预期：设置expect_out（0，字符串）“ps-ef|grep htt|grep start|wc -l \r\n11\r\n"
预期：设置 expect_out(1,string) "1"
期望：设置 expect_out(spawn_id) "exp5" 期望：设置 expect_out(缓冲区) "ps -ef|grep htt|grep start|wc -l \r\n11\r\n"
theNum = 1
不是好的

命令行实际上returns一个数字“11”，但是(\d+)捕获一个'1' 代替。

提前感谢您的意见。

Answer 1

这是由于前导 .* 的贪婪——因为它吞噬了尽可能多的字符，(\d+) 部分剩余的文本是 last 数字。这是一个演示，其中我还捕获了领先的 ".*":

expect1.11> exp_internal 1
expect1.12> spawn sh -c {echo foo; echo 1234; echo bar}
spawn sh -c echo foo; echo 1234; echo bar
parent: waiting for sync byte
parent: telling child to go ahead
parent: now unsynchronized from child
spawn: returns {78523}
78523
expect1.13> expect -re {(.*)(\d+).*}
Gate keeper glob pattern for '(.*)(\d+).*' is ''. Not usable, disabling the performance booster.

expect: does "" (spawn_id exp10) match regular expression "(.*)(\d+).*"? (No Gate, RE only) gate=yes re=no
foo
1234
bar

expect: does "foo\r\n1234\r\nbar\r\n" (spawn_id exp10) match regular expression "(.*)(\d+).*"? (No Gate, RE only) gate=yes re=yes
expect: set expect_out(0,string) "foo\r\n1234\r\nbar\r\n"
expect: set expect_out(1,string) "foo\r\n123"
expect: set expect_out(2,string) "4"
expect: set expect_out(spawn_id) "exp10"
expect: set expect_out(buffer) "foo\r\n1234\r\nbar\r\n"

记下“1,string”和“2,string”中存储的内容

解决方案是简化您的正则表达式。如果您只想捕获 first 组数字，请使用

expect -re {\d+}
set theNum $expect_out(0,string)

或者，如果您想捕获第一个数字 那是一行中唯一的字符：

expect -re {\r\n(\d+)\r\n}
set theNum $expect_out(1,string)

这里的一个教训是，您通常不需要在正则表达式模式中使用前导和结尾 .* 通配符：只需关注捕获所需文本所需的内容即可。

EXPECT 脚本中的正则表达式模式匹配

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