Find the line number which contains the pattern using custom regex delimiter

As in example I’m trying to get line numbers which contains the pattern. My pattern contains slashes so I wanted to add custom delimiter.

This simple one works:

sed -n '/file/=' temp.txt

Using delimiter for string replace works too:

sed 's|file|gile|' temp.txt

but when I want to add delimiter to first example it doesn’t:

sed -n '|file /etc|=' temp.txt

I know I can escape slashes but I would prefer to add custom delimiter. Any idea how to fix my command?

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Answers:

Method 1

Method 2

Answers:

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Method 1

Stéphane gave you the sed solution:

sed -n  '|file /etc|=' file

If you’re open to using other tools, you can also do

grep -n 'file /etc' file

That will also print the line itself, to get the line number alone try:

grep -n 'file /etc' file | cut -d: -f 1

Or, you can use perl:

perl -lne 'm|file /etc| && print $.' file

Or awk:

awk '$0 ~ "file /etc" {print NR}'

Method 2

In all context addresses, you have to escape the opening delimiter, unless you’re using the default /. Any following occurrences that are escaped are treated as the literal character, not as the ending delimiter.

default delimiter:
```
/start/,/end/{/pattern/d;}
```
custom delimiter:
```
#start#,#end#{#pattern#d;}
```

See the POSIX docs:

In a context address, the construction cREc where c is any character
other than a backslash or newline character, is identical to /RE/ If
the character designated by c appears following a backslash, then it
is considered to be that literal character, which does not terminate
the RE. For example, in the context address xabcxdefx, the second x
stands for itself, so that the regular expression is abcxdef.

Similar description in GNU sed man page:

/regexp/
       Match lines matching the regular expression regexp.      
cregexpc
       Match lines matching the regular expression regexp.  
       The c may be any character.

and FreeBSD sed man page:

In a context address, any character other than a backslash (``'')
or newline character may be used to delimit the regular expression.
The opening delimiter   needs to be preceded by a backslash unless it
is a slash.  For example, the   context address xabcx is equivalent
to /abc/.  Also, putting a backslash character before   the delimiting
character within the regular expression causes the character to be
treated literally.  For example, in the context address xabcxdefx,
the RE delimiter is an ``x'' and the second ``x'' stands for itself,
so that the regular expression is ``abcxdef''.

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0

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