差-输出行号

Question

我想使用cli工具进行文件比较，并且需要输出行之前的行号，以帮助我跳到行差，因为我使用的工具可以理解在哪里跳转，如果行的开头类似于这个:line-number: regular line contents。

因此，我尝试了diff，阅读文档似乎是可能的：

  -D, --ifdef=NAME                output merged file with `#ifdef NAME' diffs
      --GTYPE-group-format=GFMT   format GTYPE input groups with GFMT
      --line-format=LFMT          format all input lines with LFMT
      --LTYPE-line-format=LFMT    format LTYPE input lines with LFMT
    These format options provide fine-grained control over the output
      of diff, generalizing -D/--ifdef.
    LTYPE is `old', `new', or `unchanged'.  GTYPE is LTYPE or `changed'.
    GFMT (only) may contain:
      %<  lines from FILE1
      %>  lines from FILE2
      %=  lines common to FILE1 and FILE2
      %[-][WIDTH][.[PREC]]{doxX}LETTER  printf-style spec for LETTER
        LETTERs are as follows for new group, lower case for old group:
          F  first line number
          L  last line number
          N  number of lines = L-F+1
          E  F-1
          M  L+1
      %(A=B?T:E)  if A equals B then T else E
    LFMT (only) may contain:
      %L  contents of line
      %l  contents of line, excluding any trailing newline
      %[-][WIDTH][.[PREC]]{doxX}n  printf-style spec for input line number
    Both GFMT and LFMT may contain:
      %%  %
      %c'C'  the single character C
      %c'\OOO'  the character with octal code OOO
      C    the character C (other characters represent themselves)

但是，对于这种复杂的转换，没有任何例子或解释。

是否有可能从diff获得这样的输出？如果是的话，怎么做？

Answer 1

是的，这是可能的。在使用这些选项时，默认的做法是打印出每一行。这是非常冗长的，不是你想要的。

diff --unchanged-line-format=""

将消除没有变化的行，所以现在只产生旧行和新行。

diff --unchanged-line-format="" --new-line-format=":%dn: %L"

现在将显示以:<linenumber>:和空格为前缀的新行，但仍然打印旧行。假设你想消灭他们，

diff --unchanged-line-format="" --old-line-format="" --new-line-format=":%dn: %L"

如果你想打印旧行而不是新行，那就把它们换一圈。