[SOLVED] Delete the lines from file between pattern match

Issue

How to delete all the lines between two pattern in file using sed.

Here pattern are //test and //endtest, file content:

blah blah blah
c
f
f
[
]
//test
all text to be deleted 
line1
line2
xyz
amv
{
//endtest
l
dsf
dsfs

Expected result:

blah blah blah
c
f
f
[
]
//test
//endtest
l
dsf
dsfs

Solution

This is common feature of sed

 sed '/^\/\/test$/,/^\/\/endtest/d'

As / is used to bound regex, they have to be escaped, in regex.

If you want to keep marks (as requested):

sed '/^\/\/test$/,/^\/\/endtest/{//!d}'

Explanation:

Have a look at info sed, search for sed address -> Regexp Addresses and Range Addresses.

Enclosed by { ... }, symbol // mean any bound.

The empty regular expression '//' repeats the last regular expression match (the same holds if the empty regular expression is passed to the 's' command).

! mean not, then d for delete line

Alternative: You could write:

sed '/^\/\/\(end\)\?test$/,//{//!d}' 

or

sed -E '/^\/\/(end)?test$/,//{//!d}'

Will work same, but care, this could reverse effect if some extra pattern //endtest may exist before first open pattern (//test).

... All this was done, using GNU sed 4.4!

Under MacOS, BSD sed

Under MacOS, I've successfully dropped wanted lines with this syntax:

sed '/^\/\/test$/,/^\/\/endtest/{/^\/\/\(end\)\{0,1\}test$/!d;}'

or

sed -E '/^\/\/test$/,/^\/\/endtest/{/^\/\/(end)?test$/!d;}'

Answered By - F. Hauri