我需要处理大文件，并且必须找到两个文件之间的差异。我不需要不同的位，而是差异的数量。
找出我想出的不同行的数量
diff --suppress-common-lines --speed-large-files -y File1 File2 | wc -l
它确实有效，但是有更好的方法吗？
以及如何计算差异的确切数量（使用 bash、diff、awk、sed 等旧版本的 perl 等标准工具）？
如果您想计算不同的行数，请使用以下命令：
diff -U 0 file1 file2 | grep ^@ | wc -l
约翰的回答没有重复计算不同的行吗？
diff -U 0 file1 file2 | grep -v ^@ | wc -l
diff如果使用 Linux/Unix，可以使用
comm -1 file1 file2comm -1 file1 file2 | wc -lcomm -2 ...由于每个不同的输出行都以
<>diff file1 file2 | grep ^[\>\<] | wc -l
通过在脚本行中仅使用
\<\>我相信正确的解决方案就在这个答案，即：
$ diff -y --suppress-common-lines a b | grep '^' | wc -l
1
如果您正在处理具有类似内容的文件，这些文件应该按相同的行进行排序（例如描述类似内容的 CSV 文件），并且您会例如想要在以下文件中找到 2 个差异：
File a: File b:
min,max min,max
1,5 2,5
3,4 3,4
-2,10 -1,1
你可以像这样用Python实现它：
different_lines = 0
with open(file1) as a, open(file2) as b:
for line in a:
other_line = b.readline()
if line != other_line:
different_lines += 1
这是一种计算两个文件之间任何类型差异的方法，并为这些差异指定正则表达式 - 这里
.git diff --patience --word-diff=porcelain --word-diff-regex=. file1 file2 | pcre2grep -M "^@[\s\S]*" | pcre2grep -M --file-offsets "(^-.*\n)(^\+.*\n)?|(^\+.*\n)" | wc -l
摘自
man git-diff--patience Generate a diff using the "patience diff" algorithm. --word-diff[=<mode>] Show a word diff, using the <mode> to delimit changed words. By default, words are delimited by whitespace; see --word-diff-regex below. porcelain Use a special line-based format intended for script consumption. Added/removed/unchanged runs are printed in the usual unified diff format, starting with a +/-/` ` character at the beginning of the line and extending to the end of the line. Newlines in the input are represented by a tilde ~ on a line of its own. --word-diff-regex=<regex> Use <regex> to decide what a word is, instead of considering runs of non-whitespace to be a word. Also implies --word-diff unless it was already enabled. Every non-overlapping match of the <regex> is considered a word. Anything between these matches is considered whitespace and ignored(!) for the purposes of finding differences. You may want to append |[^[:space:]] to your regular expression to make sure that it matches all non-whitespace characters. A match that contains a newline is silently truncated(!) at the newline. For example, --word-diff-regex=. will treat each character as a word and, correspondingly, show differences character by character.
pcre2greppcre2-utils我很想编辑@Josh或@John的答案，但编辑队列已满，所以这里是：
diff -U 0 file1 file2 | tail -n +3 | grep -c '^@'
为什么？
diff -U 0 file1 file2
输出类似：
--- file1 (+ timestamp)
+++ file2 (+ timestamp)
@@ range information for first difference @@
+ some added
+ lines
@@ range info for second difference @@
- some
- removed
- lines
@@ range info for edit @@
- I changed
- this
+ into
+ these new
+ lines
有关范围信息的更多信息，请参阅此答案
所以：
tail -n +3grep -c '^@'因此，输出是差异的计数，这里“差异”被视为经过修改的范围。
但不同之处在于我指的是修改行的计数！
因为，正如其他答案中所指出的，对单行的修改将显示两次，既作为删除
-+给你：
diff -U 0 file1 file2 | tail -n +3 | perl -ne 'if (/^\+/) { $add +=1 }; if (/^-/) { $del += 1 }; END { if (!$add) { $add=0 }; if (!$del) { $del=0 }; print "+$add -$del\n"}'
perl“one-liner”有什么作用？
if (/^\+/) { $add +=1 }; # counts the number of added lines, starting with +
if (/^-/) { $del += 1 }; # counts the number of deleted lines, starting with -
END {
if (!$add) { $add=0 }; # set count to 0 if no added line
if (!$del) { $del=0 }; # set count to 0 if no deleted line
print "+$add -$del\n" # print the count of added lines and the count of deleted lines
}
输出示例：
+23 -10