testprintf.pl：
~~~~~~~~~~~~~
#!/usr/bin/perl
printf ("12345678901234567890\n");
printf ("XXXX%6dXXXXXXXXXX\n", 1234);
printf ("XXXX%6dXXXXXXXXXX\n", 1234567);
printf ("XXXX%06dXXXXXXXXXX\n", 1234);
printf ("XXXX%06dXXXXXXXXXX\n", 1234567);
printf ("XXXX%-6dXXXXXXXXXX\n", 1234);
printf ("XXXX%6sXXXXXXXXXX\n", "abc");
printf ("XXXX%6.2sXXXXXXXXXX\n", "abc");
printf ("XXXX%2sXXXXXXXXXX\n", "");
printf ("XXXX%2sXXXXXXXXXX\n", "2");
printf ("XXXX%2sXXXXXXXXXX\n", "23");
printf ("XXXX%2.2sXXXXXXXXXX\n", "");
printf ("XXXX%2.2sXXXXXXXXXX\n", "2");
printf ("XXXX%2.2sXXXXXXXXXX\n", "23");

出力結果：
~~~~~~~~
12345678901234567890
XXXX  1234XXXXXXXXXX
XXXX1234567XXXXXXXXXX
XXXX001234XXXXXXXXXX
XXXX1234567XXXXXXXXXX
XXXX1234  XXXXXXXXXX
XXXX   abcXXXXXXXXXX
XXXX    abXXXXXXXXXX
XXXX  XXXXXXXXXX
XXXX 2XXXXXXXXXX
XXXX23XXXXXXXXXX
XXXX  XXXXXXXXXX
XXXX 2XXXXXXXXXX
XXXX23XXXXXXXXXX