右对齐一行中的最后一个单词

debugcn 发表于 Dev

死灵

…并非在每一行中都存在

|标记行的最大长度的示例，例如不包括行尾的 79 个字符，并且SPECIAL_WORD是标题中提到的最后一个单词：

Some words with(some = ! characters, beside ASCII) sdsdds                     |
Some words with(some = ! characters, beside ASCII)   SPECIAL_WORD             |
                                                                              |
Some words (some = ! characters, beside ASCII)  as  SPECIAL_WORD              |
Some words (some = ! characters, beside ASCII) asdb asd                       |
foobar blah SPECIAL_WORD                                                      |
eside ASCII) asdb asd eside ASCII) asdb asd eside ASCII) asdb asd eside ASCII)| asdb asd SPECIAL_WORD
Some words (some = ! characters, be                                           |
Some words (some = ! characters, beSome words (some = ! characters, be SPECIAL|_WORD
Some words (some = ! characters, beside ASCII)  as  SPECIAL_WORD              |
                                                                              |
                                                                              |
Some words (some = ! characters, beside ASCII)  as                SPECIAL_WORD|
Some words (some = ! characters, beside ASCII)  as                   SPECIAL_W|ORD
Some words (some = ! characters, beside ASCII) asdb asd                       |
                                                                              |
Some words (some SPECIAL_WORD = ! characters, beside ASCII) asdb asd          |
                                                                              |

预期输出：

Some words with(some = ! characters, beside ASCII) sdsdds                     |
Some words with(some = ! characters, beside ASCII)                SPECIAL_WORD|
                                                                              |
Some words (some = ! characters, beside ASCII)  as                SPECIAL_WORD|
Some words (some = ! characters, beside ASCII) asdb asd                       |
foobar blah                                                       SPECIAL_WORD|
eside ASCII) asdb asd eside ASCII) asdb asd eside ASCII) asdb asd eside ASCII)| asdb asd SPECIAL_WORD
Some words (some = ! characters, be                                           |
Some words (some = ! characters, beSome words (some = ! characters, be SPECIAL|_WORD
Some words (some = ! characters, beside ASCII)  as                SPECIAL_WORD|
                                                                              |
                                                                              |
Some words (some = ! characters, beside ASCII)  as                SPECIAL_WORD|
Some words (some = ! characters, beside ASCII)  as                SPECIAL_WORD|
Some words (some = ! characters, beside ASCII) asdb asd                       |
                                                                              |
Some words (some SPECIAL_WORD = ! characters, beside ASCII) asdb asd          |
                                                                              |

相当混乱，不是吗？我尝试实施的规则是：

右对齐SPECIAL_WORD使得

的最后一个字符SPECIAL_WORD应位于第 79 列，行尾字符之前的最后一个字符
ifSPECIAL_WORD后跟除行尾字符以外的任何字符，该行不应被触及
如果包含的行SPECIAL_WORD已经超过允许的长度，则不应触摸，除非左侧有足够的空间SPECIAL_WORD
如果该行的最后一个字符与该行SPECIAL_WORD的第一个字符之间没有空格，则SPECIAL_WORD不得触及 5- 如果右对齐后的行SPECIAL_WORD长度超过该行不得触及的限制
SPECIAL_WORD 可能包含多个单词，但应视为一个单元
SPECIAL_WORD 仅由 ASCII 字符组成。
它始终是一行，不会有换行符 SPECIAL_WORD

我尝试了像col, column, fmt, format, Bash 之类的常见嫌疑人，printf这里列出的大多数想法（awk，简短的 shell 脚本片段sed等等），但一切都是某种“接近但没有雪茄”。我已经降低了规则的严格性，因此我不得不忽略的其中一个函数/脚本现在可能会起作用，但是太多了，无法记住所有这些。

在我坐下来写一个完整的解析器来做它之前，让我在这里问一下我的问题是否有更简单的解决方案。

由于正确的坚持让我发布我在这里尝试的内容是最接近的：

cat format_test  | perl -e 'my $len;foreach my $line ( <STDIN> ) {$line =~ /^$/ and print $line and next;$line =~ /^(.+?)( *?)(SPECIAL_WORD)?$/;$len = 79-(length($1));  printf("%s%${len}s\n", $1,$3);}'

（cat用于明确输入来自管道）

我向每位 Perl 程序员致以最深切的歉意！

那个小可憎的输出：


Some words with(some = ! characters, beside ASCII) sdsdds                      
Some words with(some = ! characters, beside ASCII)                 SPECIAL_WORD

Some words (some = ! characters, beside ASCII)  as                 SPECIAL_WORD
Some words (some = ! characters, beside ASCII) asdb asd                        
foobar blah                                                        SPECIAL_WORD
eside ASCII) asdb asd eside ASCII) asdb asd eside ASCII) asdb asd eside ASCII) asdb asdSPECIAL_WORD
Some words (some = ! characters, be                                            
Some words (some = ! characters, beSome words (some = ! characters, beSPECIAL_WORD
Some words (some = ! characters, beside ASCII)  as                 SPECIAL_WORD


Some words (some = ! characters, beside ASCII)  as                 SPECIAL_WORD
Some words (some = ! characters, beside ASCII)  as                 SPECIAL_WORD
Some words (some = ! characters, beside ASCII) asdb asd                        

Some words (some SPECIAL_WORD = ! characters, beside ASCII) asdb asd

这在它不应该的行上工作。

斯蒂芬·查泽拉斯

使用perl, 并假设所有字符都是单宽的：

perl -Mopen=locale -lspe '
  BEGIN{$pad = $width - 1 - length $word}
  s/(.*?)\s+\Q$word\E$/sprintf "%-*s %s", $pad, $1, $word/e
' -- -width=79 -word=SPECIAL_WORD < your-file

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