perl脚本

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文件内容的追加，覆盖（>>,>）

#!/usr/bin/perl
open ( readfile , "file4read.txt") or die ("Could not open the filen");
open ( writefile , ">b" );
while( $line =  )
{
    print writefile $line;
}
close( writefile );
close( readfile );

 

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文件打开判断

[root@localhost wangzm]# vi a1.sh

#!/usr/bin/perl
     if (open(MYFILE, "b")) {
     die ("here's what to do if the file opened successfully\n");
     }
     unless (open (MYFILE, "b")) {
     die ("cannot open input file file1\n");
     }

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数组的应用

[root@localhost wangzm]# cat a1.sh
#!/usr/bin/perl
@array = (1, 2, 3, 4);
$array[3] = 5; # now @array is (1,2,3,5)
$array[6] = 17; # now @array is (1,2,3,5,"","",17);

print ("$array[0],$array[1],$array[2],$array[3],$array[4],$array[5],$array[6]\n")

[root@localhost wangzm]# ./a1.sh
1,2,3,5,,,17

==========================================

while 循环

[root@localhost wangzm]# cat a1.sh
#!/usr/bin/perl
  $line = "abc";
  $count = 1;
  while ($count <= 3) {
    print ("$line\n");
    $line = "def";
    $count++;
  }

[root@localhost wangzm]# ./a1.sh
abc
def
def

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for循环

[root@localhost wangzm]# cat a1.sh
#!/usr/bin/perl
  for ($line = "abc", $count = 1; $count <= 3;   $line = "def", $count++) {
    print ("$line\n");
  }
[root@localhost wangzm]# ./a1.sh
abc
def
def

===========================================