Awk 不改变顺序的连续行

我期待着grep文件1与相同的顺序和两个以上的连续行。我试过这个：

cat file1
4    
8     
7  

cat file2
4.999286    12.669064   0.000000  
5.999343    12.753258   0.000000  
6.999401    12.654514   0.000000  
7.999458    12.774485   0.000000  
8.999515    12.662147   0.000000  
9.999572    12.700071   0.000000  
10.999629   12.717721   0.000000  

我希望输出如下：

grep -A 2 -Ff file1 file2

---

grep

对于很少的文件扫描速度很快

4.999286    12.669064   0.000000  
5.999343    12.753258   0.000000  
6.999401    12.654514   0.000000  
8.999515    12.662147   0.000000  
9.999572    12.700071   0.000000  
10.999629   12.717721   0.000000  
7.999458    12.774485   0.000000  
8.999515    12.662147   0.000000  
9.999572    12.700071   0.000000 

$while IFS=read-r n；dogrep-A2“^$n”文件2；完成<文件1
4.999286 12.669064 0.000000
5.999343 12.753258 0.000000
6.999401 12.654514 0.000000
8.999515 12.662147 0.000000
9.999572 12.700071 0.000000
10.999629 12.717721 0.000000
7.999458 12.774485 0.000000
8.999515 12.662147 0.000000
9.999572 12.700071 0.000000

请您尝试以下操作，这将以输入文件1中出现

$1

的相同顺序给出结果

$ while IFS= read -r n; do grep -A2 "^$n." file2; done < file1

4.999286 12.669064 0.000000
5.999343 12.753258 0.000000
6.999401 12.654514 0.000000
8.999515 12.662147 0.000000
9.999572 12.700071 0.000000
10.999629 12.717721 0.000000
7.999458 12.774485 0.000000
8.999515 12.662147 0.000000
9.999572 12.700071 0.000000

---

---

解释：为上述代码添加解释

awk '
BEGIN{
  s1="\""
}
FNR==NR{
  a[$0]
  next
}
(int($1) in a){
  system("grep -A2 " s1 $0 s1 OFS FILENAME)
}
'  Input_file1  Input_file2

输出如下

awk '                                             ##Starting awk program here.
BEGIN{                                            ##Starting BEGIN section of code here.
  s1="\""                                         ##Creating a variable named s1 whose value is "
}                                                 ##Closing BEGIN section of awk code here.
FNR==NR{                                          ##Checking condition if FNR==NR, which will be only TRUE when Input_file1 is being read.
  a[$0]                                           ##Creating an array named a whose index is $0.
  next                                            ##next will skip all further statements from here.
}                                                 ##Closing BLOCK for FNR==NR condition here.
(int($1) in a){                                   ##Checking condition if integer value of $1 is present in array a then do following.
  system("grep -A2 " s1 $0 s1 OFS FILENAME)       ##Using system command to run grep command which will print 2 lines after match of current line in current Input_file name passed to grep by FILENAME variable of awk.
}                                                 ##Closing BLOCK of condition.
'  Input_file1  Input_file2                       ##Mentioning Input_file names here.

这可能适合您（GNU&）：

使用file1作为输入并保持原始顺序，grepfile2并行执行多次

或者，如果您愿意，可以是：

parallel -k grep -A2 '^{}' file2 :::: file1

或：

---

@莫德，你能告诉我这是否对你有帮助吗？如果这对你有帮助，你能检查一下我的答案吗？

parallel -k grep -A2 '^{}' file2 :::: file1

parallel -a file1 -k grep -A2 '^{}' file2

cat file1 | parallel -k grep -A2 '^{}' file2