比较linux终端中的两个文件
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Comparing two files in linux terminal
提问by Ali Imran
There are two files called "a.txt"and "b.txt"both have a list of words. Now I want to check which words are extra in "a.txt"and are not in "b.txt".
有两个名为“a.txt”和“b.txt”的文件都有一个单词列表。现在我想检查哪些单词在"a.txt" 中是多余的，而不是在"b.txt" 中。
I need a efficient algorithm as I need to compare two dictionaries.
我需要一个有效的算法，因为我需要比较两个字典。
采纳答案by Ali Imran
Here is my solution for this :
这是我的解决方案：
mkdir temp
mkdir results
cp /usr/share/dict/american-english ~/temp/american-english-dictionary
cp /usr/share/dict/british-english ~/temp/british-english-dictionary
cat ~/temp/american-english-dictionary | wc -l > ~/results/count-american-english-dictionary
cat ~/temp/british-english-dictionary | wc -l > ~/results/count-british-english-dictionary
grep -Fxf ~/temp/american-english-dictionary ~/temp/british-english-dictionary > ~/results/common-english
grep -Fxvf ~/results/common-english ~/temp/american-english-dictionary > ~/results/unique-american-english
grep -Fxvf ~/results/common-english ~/temp/british-english-dictionary > ~/results/unique-british-english
回答by Anders Johansson
Sort them and use comm:
对它们进行排序并使用comm：
comm -23 <(sort a.txt) <(sort b.txt)
commcompares (sorted) input files and by default outputs three columns: lines that are unique to a, lines that are unique to b, and lines that are present in both. By specifying -1, -2and/or -3you can suppress the corresponding output. Therefore comm -23 a blists only the entries that are unique to a. I use the <(...)syntax to sort the files on the fly, if they are already sorted you don't need this.
comm比较（排序）输入文件并默认输出三列：a 独有的行、b 独有的行以及两者中都存在的行。通过指定-1,-2和/或-3您可以抑制相应的输出。因此comm -23 a b只列出了 a 唯一的条目。我使用<(...)语法对文件进行动态排序，如果它们已经排序，则不需要它。
回答by Manjula
You can use difftool in linux to compare two files. You can use --changed-group-formatand --unchanged-group-formatoptions to filter required data.
您可以使用difflinux 中的工具来比较两个文件。您可以使用--changed-group-format和--unchanged-group-format选项来过滤所需的数据。
Following three options can use to select the relevant group for each option:
以下三个选项可用于为每个选项选择相关组：
'%<' get lines from FILE1
'%>' get lines from FILE2
'' (empty string) for removing lines from both files.
'%<' 从 FILE1 中获取行
'%>' 从 FILE2 中获取行
''（空字符串）用于从两个文件中删除行。
E.g: diff --changed-group-format="%<" --unchanged-group-format="" file1.txt file2.txt
例如：diff --changed-group-format="%<" --unchanged-group-format="" file1.txt file2.txt
[root@vmoracle11 tmp]# cat file1.txt
test one
test two
test three
test four
test eight
[root@vmoracle11 tmp]# cat file2.txt
test one
test three
test nine
[root@vmoracle11 tmp]# diff --changed-group-format='%<' --unchanged-group-format='' file1.txt file2.txt
test two
test four
test eight
回答by Chris Seymour
Use comm -13(requires sorted files):
使用comm -13（需要排序文件）：
$ cat file1
one
two
three
$ cat file2
one
two
three
four
$ comm -13 <(sort file1) <(sort file2)
four
回答by Fengya Li
if you have vim installed,try this:
如果你安装了 vim，试试这个：
vimdiff file1 file2
or
或者
vim -d file1 file2
you will find it fantastic.
你会发现它很棒。
回答by mudrii
Try sdiff(man sdiff)
试试sdiff( man sdiff)
sdiff -s file1 file2
回答by FindlinuxOne
You can also use: colordiff: Displays the output of diff with colors.
您还可以使用：colordiff：用颜色显示 diff 的输出。
About vimdiff: It allows you to compare files via SSH, for example :
关于vimdiff：它允许您通过 SSH 比较文件，例如：
vimdiff /var/log/secure scp://192.168.1.25/var/log/secure
Extracted from: http://www.sysadmit.com/2016/05/linux-diferencias-entre-dos-archivos.html
摘自：http: //www.sysadmit.com/2016/05/linux-diferencias-entre-dos-archivos.html
回答by joelostblom
If you prefer the diff output style from git diff, you can use it with the --no-indexflag to compare files not in a git repository:
如果您更喜欢 diff 输出样式git diff，您可以将它与--no-index标志一起使用来比较不在 git 存储库中的文件：
git diff --no-index a.txt b.txt
Using a couple of files with around 200k file name strings in each, I benchmarked (with the built-in timecommand) this approach vs some of the other answers here:
使用几个包含大约 20 万个文件名字符串的文件，我对time这种方法与这里的其他一些答案进行了基准测试（使用内置命令）：
git diff --no-index a.txt b.txt
# ~1.2s
comm -23 <(sort a.txt) <(sort b.txt)
# ~0.2s
diff a.txt b.txt
# ~2.6s
sdiff a.txt b.txt
# ~2.7s
vimdiff a.txt b.txt
# ~3.2s
commseems to be the fastest by far, while git diff --no-indexappears to be the fastest approach for diff-style output.
comm到目前为止似乎是最快的，而git diff --no-index似乎是差异式输出的最快方法。
Update 2018-03-25You can actually omit the --no-indexflag unless you are inside a git repository and want to compare untracked files within that repository. From the man pages:
更新 2018-03-25--no-index除非您在 git 存储库中并想要比较该存储库中未跟踪的文件，否则您实际上可以省略该标志。从手册页：
This form is to compare the given two paths on the filesystem. You can omit the --no-index option when running the command in a working tree controlled by Git and at least one of the paths points outside the working tree, or when running the command outside a working tree controlled by Git.
这种形式是比较文件系统上给定的两个路径。在 Git 控制的工作树中运行命令并且至少有一个路径指向工作树之外，或者在 Git 控制的工作树之外运行命令时，您可以省略 --no-index 选项。
回答by Iurii Golskyi
Also, do not forget about mcdiff- Internal diff viewer of GNU Midnight Commander.
另外，不要忘记mcdiff- GNU Midnight Commander 的内部差异查看器。
For example:
例如：
mcdiff file1 file2
Enjoy!
享受！
回答by James Brown
Using awk for it. Test files:
使用awk。测试文件：
$ cat a.txt
one
two
three
four
four
$ cat b.txt
three
two
one
The awk:
awk：
$ awk '
NR==FNR { # process b.txt or the first file
seen[four
four
] # hash words to hash seen
next # next word in b.txt
} # process a.txt or all files after the first
!($ awk '
NR==FNR {
seen[four
]
next
}
!($ cat a.txt
four,four,three,three,two,one
five,six
$ cat b.txt
one,two,three
in seen) { # if word is not hashed to seen
seen[awk -F, ' # comma-separated input
NR==FNR {
for(i=1;i<=NF;i++) # loop all comma-separated fields
seen[$i]
next
}
{
for(i=1;i<=NF;i++)
if(!($i in seen)) {
seen[$i] # this time we buffer output (below):
buffer=buffer (buffer==""?"":",") $i
}
if(buffer!="") { # output unempty buffers after each record in a.txt
print buffer
buffer=""
}
}' b.txt a.txt
] # hash unseen a.txt words to seen to avoid duplicates
print # and output it
}' b.txt a.txt
in seen)' b.txt a.txt # if word is not hashed to seen, output it
Duplicates are outputed:
输出重复项：
four
five,six
To avoid duplicates, add each newly met word in a.txt to seenhash:
为避免重复，将 a.txt 中每个新遇到的单词添加到seen哈希中：
Output:
输出：
##代码##If the word lists are comma-separated, like:
如果单词列表以逗号分隔，例如：
##代码##you have to do a couple of extra laps (forloops):
你必须多做几圈（for循环）：
Output this time:
这次输出：
##代码##