shell - (shell) 如何从一个文件中删除可以在另一个文件中找到的字符串？

Question

file1.txt

aaaa
bbbb
cccc
dddd
eeee

file2.txt

DDDD
cccc
aaaa

结果

bbbb
eeee

如果能不区分大小写就更好了!

谢谢!

Answer 1

grep 可以匹配从文件中读取的模式，并打印出所有不匹配该模式的行。也可以不区分大小写地匹配，比如

grep -vi -f file2.txt file1.txt

手册页摘录:

SYNOPSIS
   grep [OPTIONS] PATTERN [FILE...]
   grep [OPTIONS] [-e PATTERN | -f FILE] [FILE...]

   -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.)ns zero
          patterns, and therefore matches nothing.  (-f is specified by POSIX.)
   -i, --ignore-case
          Ignore case distinctions in both the PATTERN and the input  files.   (-i  is
          specified by POSIX.)ions in both the PATTERN and the input  files.   (-i  is
          specified by POSIX.)
   -v, --invert-match
          Invert  the  sense  of  matching,  to  select  non-matching  lines.   (-v is
          specified by POSIX.)of  matching,  to  select  non-matching  lines.   (-v is
          specified by POSIX.)