Perl：内联变量替换不起作用

Question

下面是perl脚本

    my $var="
    @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
    @    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
    @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
    IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
    Someone could be eavesdropping on you right now (man-in-the-middle attack)!
    It is also possible that the RSA host key has just been changed.
    The fingerprint for the RSA key sent by the remote host is
    da:be:66:35:0e:47:0f:60:f1:70:a4:43:ff:39:da:65.
    Please contact your system administrator.
    Add correct host key in /home/PCS/.ssh/known_hosts to get rid of this message.
    Offending key in /home/PCS/.ssh/known_hosts:144
    Password authentication is disabled to avoid man-in-the-middle attacks.
    Keyboard-interactive authentication is disabled to avoid man-in-the-middle attacks.
    Filesystem                 1K-blocks       Used  Available Use% Mounted on
    /dev/mapper/vg00-lscratch 7288301568 6079377352 1208924216  84% /scratch
    ";
    
    $var =~ s/.+Filesystem/Filesystem/g;
    print "$var\n";

打印的是（$var值）：

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that the RSA host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
da:be:66:35:0e:47:0f:60:f1:70:a4:43:ff:39:da:65.
Please contact your system administrator.
Add correct host key in /home/PCS/.ssh/known_hosts to get rid of this message.
Offending key in /home/PCS/.ssh/known_hosts:144
Password authentication is disabled to avoid man-in-the-middle attacks.
Keyboard-interactive authentication is disabled to avoid man-in-the-middle attacks.
Filesystem22                 1K-blocks       Used  Available Use% Mounted on
/dev/mapper/vg00-lscratch 7288301568 6079377352 1208924216  84% /scratch

替换似乎不起作用。

据我所知， $var 应该打印以下内容，但事实并非如此。怎么办呢？这个替换有什么问题吗？

Filesystem                 1K-blocks       Used  Available Use% Mounted on
/dev/mapper/vg00-lscratch 7288301568 6079377352 1208924216  84% /scratch

Answer 1

.

匹配 LF 以外的任何字符。但你想匹配任何字符。您可以使用

/s

来做到这一点。

s/.+Filesystem/Filesystem/sg

澄清

Filesystem

出现在行首：

s/.+^Filesystem/Filesystem/msg

防止匹配失败时不必要的回溯：

s/\A.+^Filesystem/Filesystem/msg

防止重复：

s/\A.+^(?=Filesystem)//msg