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从一个 grep 到另一个 grep

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从一个 grep 到另一个 grep

如何从另一个文件中获取一个文件的内容

假设我有一个文件“file1”，它有

a
b
c

另一个文件“file2”包含

a
b
c
d
e
f

我通常会这样做

cat file2 | grep -v a | grep -v b | grep -v c

有没有办法用文件做到这一点

grep -v file2 file1

答案1

用于diff查找差异并sed选择、格式化和打印仅添加的行：

diff file1 file2 | sed -n "/^>/{s/> //;p}"

添加：

如果文件的顺序不同，则sort先排序它们两个，然后再排序diff它们。

sort file1 > file1.s
sort file2 > file2.s
diff file1.s file2.s | sed -n "/^>/{s/> //;p}"

如果您正在使用bash，则可以使用<(...)流程替换：

diff <(sort file1) <(sort file2) | sed -n "/^>/{s/> //;p}"

答案2

GNU grep (我想其他人也一样) 可以采用以下-f选项：

   -f FILE, --file=FILE
          Obtain patterns from FILE, one  per  line.   The  empty
          file  contains  zero  patterns,  and  therefore matches
          nothing.  (-f is specified by POSIX.)

因此，你可以这样做：

grep -vFf file1 file2

下列的妮可·汉密尔顿根据评论中的建议，我添加了“-F”选项，这导致 grep 将其 PATTERN（在本例中为 file1 中的每一行）解释为固定字符串而不是正则表达式：

  -F, --fixed-strings
          Interpret PATTERN as  a  list  of  fixed  strings,  separated  by
          newlines,  any  of  which  is to be matched.  (-F is specified by
          POSIX.)

我也写过PERL 脚本还有更多选项：

$ list_compare.pl -h

  USAGE: compare_lists.pl FILE1 FILE2

  This script will compare FILE1 and FILE2, searching for the 
  contents of FILE1 in FILE2 (and NOT vice-versa). FILE one must 
  be one search pattern per line, the search pattern need only be 
  contained within one of the lines of FILE2.

OPTIONS: 
  -c : Print patterns COMMON to both files
  -f : Search only the first characters (until the 1st space) of each line of 
       FILE2 for the search pattern given in FILE1. So, if FILE1 contains
       "foo bar", only "foo" will be taken as a pattern (MUCH faster).
  -d : Print duplicate entries     
  -m : Print patterns MISSING in FILE2 (default)
  -h : Print this help and exit

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