Question

我有两个文件，我使用“comm -23 file1 file2”命令将不同文件的行提取到另一个文件。

我还需要提取不同行的东西，但也保留字符串“line_ $ NR”。例：文件1：

line_1: This is line0
line_2: This is line1
line_3: This is line2
line_4: This is line3

file2的：

line_1: This is line1
line_2: This is line2
line_3: This is line3

我需要这个输出：差异file1 file2：

line_1: This is line0.

总之，我需要提取差异，就像文件开头没有line_ $ NR一样，但是当我打印结果时，我还需要打印line_ $ NR。

Answer 1

尝试使用awk

awk -F: 'NR==FNR {a[$2]; next} !($2 in a)' file2 file1

输出：

line_1: This is line0

简短说明

awk -F: '             # Set filed separator as ':'. $1 contains line_<n> and $2 contains 'This is line_<m>'
    NR==FNR {         # If Number of records equal to relative number of records, i.e. first file is being parsed
        a[$2];        # store $2 as a key in associative array 'a'
        next          # Don't process further. Go to next record.
    } 
    !($2 in a)        # Print a line if $2 of that line is not a key of array 'a'
' file2 file1

附加要求（在评论中）

如果我在一行中有多个“：”：“line_1：This：is：line0” 不起作用。我怎样才能只使用line_x

在这种情况下，请尝试关注（仅限 GNU awk ）

awk -F'line_[0-9]+:' 'NR==FNR {a[$2]; next} !($2 in a)' file2 file1

Answer 2

这个awk行更长，但无论差异位于何处，它都会起作用：

awk 'NR==FNR{a[$NF]=$0;next}a[$NF]{a[$NF]=0;next}7;END{for(x in a)if(a[x])print a[x]}' file1 file2

试验：

kent$  head f*
==> f1 <==
line_1: This is line0
line_2: This is line1
line_3: This is line2
line_4: This is line3

==> f2 <==
line_1: This is line1
line_2: This is line2
line_3: This is line3

#test f1 f2
kent$  awk 'NR==FNR{a[$NF]=$0;next}a[$NF]{a[$NF]=0;next}7;END{for(x in a)if(a[x])print a[x]}' f1 f2
line_1: This is line0

#test f2 f1:    
kent$  awk 'NR==FNR{a[$NF]=$0;next}a[$NF]{a[$NF]=0;next}7;END{for(x in a)if(a[x])print a[x]}' f2 f1
line_1: This is line0

使用Bash从文件中提取不同的行

2 个答案: