grep 匹配一个模式的行，以及匹配前后的行直到不同的模式 [英] grep lines matching a pattern, and the lines before and after the matching until different pattern

问题描述

Start_pattern
abc
d End_pattern
Start_pattern
abc
d
ef
ghij 
klm
no End_pattern
Start_pattern
abc
def
hij End_pattern
Start_pattern
abc
dhi
jklm End_pattern

期望输出:

打印 Start_pattern 之间的行，包括 Search_pattern End_pattern 包含开始和结束模式.

To print lines between Start_pattern including Search_pattern End_pattern Start and End pattern inclusive.

Start_pattern
abc
d
ef
ghij 
klm
no End_pattern
Start_pattern
abc
def
hij End_pattern

在上面的文件中，我想搜索 "ef" 并打印 "Strat_pattern" 和 "End_pattern" 之间的行.

In above file i want to search for "ef" and print lines between "Strat_pattern" and "End_pattern".

1. 已经尝试过 grep -B[NUM] 和 -A[NUM]，它们没有用，因为可能有搜索模式gef"和Start_pattern"之间的行数未知和End_pattern".
2. grep, sed , awk 任何欢迎.最好是一个班轮.
3. sed -n '/BEGIN/,/END/p' * 用于打印 Search_pattern 之间的行，即 "def" 和End_pattern.但我无法打印 Start_pattern 和 "def"
之间的行
4. 多个文件出现多次 search_pattern

1. have tried grep -B[NUM] and -A[NUM] which are not useful as there could be unknown number of lines between search pattern "gef" and "Start_pattern" and "End_pattern".
2. grep, sed , awk anything welcomed. preferentially one liner.
3. sed -n '/BEGIN/,/END/p' * works to print lines between Search_pattern which is "def" and End_pattern. but iam not able to print lines between Start_pattern and "def"
4. Multiple files present with multiple occurrences of search_pattern

推荐答案

使用gawk，支持多字符RS:

gawk 'BEGIN{RS=ORS="End_pattern"}/ef/' file

输出:

Start_pattern
abc
d
ef
ghij 
klm
no End_pattern
Start_pattern
abc
def
hij End_pattern

说明:

# Split records based on the End_pattern
BEGIN{RS=ORS="End_pattern"}

# Print records that contain the search term
/ef/

顺便说一句，出于美观的原因，您可能希望在输出的末尾附加一个换行符:

Btw, for cosmetic reasons you might want to append a newline at the end out the output:

gawk 'BEGIN{RS=ORS="End_pattern"}/ef/;END{printf "
"}' file

<小时>

PS:虽然上述解决方案仅适用于 gawk，但也可以使用与 POSIX 兼容的简单 awk 脚本来实现，这意味着它适用于任何 awk:

---

PS: While the above solution works with gawk only, it is also possible to achieve that with a simple awk script which is compatible to POSIX, meaning it works with any awk:

awk '{b=b$0"
"}/End_pattern/{if(b~/ef/){printf "%s",b};b=""}' file

说明:

# Append the current line plus a newline to b(uffer)
{b=b$0"
"}

# Once End_pattern is found ...
/End_pattern/{
    # Check if the buffer contains the search term
    if(b~/ef/){
        # Print the buffer when the term was found
        printf "%s",b
    }
    # Clear the buffer
    b=""
}

awk '{b=b$0"
"}/End_pattern/{if(b~/ef/){printf "%s",b};b=""}' file

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