foo bar baz
this and that

g/ /s//\
/g

foo
bar
baz
this
and
that

1
+,++s/^/ /
--,.jp
++,+++s/^/ /
--,.jp
,p

foo bar baz
this and that

$ awk 'BEGIN { system("ed") }'
q
$ echo hello | awk 'BEGIN { system("ed") }'
?
$

. one
+
----
echo hello
# arbitrary lines...
echo world
----
. two
. three

. one
. two
+
----
echo hello
# arbitrary lines...
echo world
----
. three

$ ed
a
foobar

$ ed
a
foobar

...
PRIORITY:4
DESCRIPTION:this
  was
  a
  triumph
COMPLETED:20180101T160000
...

/DESCRIPTION/;/^[^ ]/-1p

DESCRIPTION:this
  was
  a
  triumph

sed -n '/DESCRIPTION/,/^[^ ]/-1p' filename

sed -n '/DESCRIPTION:/,/^\S/ { /\(DESCRIPTION\|^\s\)/p }' example.ics

BEGIN { endpat = "^(DESCRIPTION|\\s)" }
/^DESCRIPTION/, $0 !~ endpat {
    if ($0 ~ endpat) {print}
}

$ bc
bash: bc: command not found
$ ed
bash: ed: command not found

apt-get install bc ed

#!/bin/sh

SALT=$(curl -L https://api.wordpress.org/secret-key/1.1/salt/) 
STRING='put your unique phrase here'
printf '%s\n' "g/$STRING/d" a "$SALT" . w | ed -s wp-config.php

*/^M
^M
define('AUTH_KEY',         '|%)Y1>vzXGRbE?`FFZX3Mq|ur?tN/,R&%@)juSc?f@bNPYm~P=aF&Fl?!HGF4V}a');
define('NONCE_SALT',       '6;KHO6=[Ta-h7.2B@3SadaIinz/6!O=GQWE(@r(<3L+X,/:[du%Q');
/**
**/^M
^M
/**^M
 * WordPress Database Table prefix.^M

$ ed hello.html 
28
,p
Hello world!

s/>.*/>My new title/p
My new title
u
.
Hello world!

s/world/& again/p
Hello world again!

$ ed -s file1.tf <<<',n'
1	# some comment
2	module "hello_world" {
3	  source = "./mydir"
4	}
5	# another comment
$ ed -s file1.tf <<<'/module.*world/,/}/p'
module "hello_world" {
  source = "./mydir"
}
$ ed -s file2.tf <<<',n'
1	# some comment
2	module "hello_world" {
3	  source = "./mydir"
4	}
5	# another comment
6	# some comment
7	module "hello_again" {
8	  source = "./anotherdir"
9	}
10	# another comment
$ ed -s file2.tf <<<'/module.*again/,/}/p'
?
$ gsed -n '/module.*again/,/}/p' file2.tf
module "hello_again" {
  source = "./anotherdir"
}

$ ed -s file2.tf <<<'?module.*again?,?}?p'
module "hello_again" {
  source = "./anotherdir"
}

$ ed -s file3.tf <<<,n
1	# some comment
2	module "hello_world" {
3	  source = "./mydir"
4	}
5	# another comment
6	# some comment
7	module "hello_again" {
8	  source = "./anotherdir"
9	}
10	# another comment
11	# some comment
12	module "hello_yet_again" {
13	  source = "./yetanotherdir"
14	}
15	# another comment
$ ed -s file3.tf <<<'?module.*hello_again?,?}?p'
module "hello_again" {
  source = "./anotherdir"
}
# another comment
# some comment
module "hello_yet_again" {
  source = "./yetanotherdir"
}