Delete Lines containing a string after a Matching patterns?-CodePudding

In my yaml file , i want to delete a block using Sed After matching a pattern .

Example:

Keypages:
- name: Key pages
LaunchPad:
- name: "\U0001F680Launch Pad"
- location: US
Microservices:
- name: 'Micro services '

In this example , when matching LaunchPad(for example) in the start of a line, i want to delete it ans its block ( for me the lines starting with - and then stop when not finding -)

Result :

Keypages:
- name: Key pages
Microservices:
- name: 'Micro services '

thank you

CodePudding user response：

Use this Perl one-liner:

perl -i.bak -ne 'print unless m{^LaunchPad} .. !m{^\s*-}' in_file

The Perl one-liner uses these command line flags:
-e : Tells Perl to look for code in-line, instead of in a file.
-n : Loop over the input one line at a time, assigning it to $_ by default.
-i.bak : Edit input files in-place (overwrite the input file). Before overwriting, save a backup copy of the original file by appending to its name the extension .bak.

EXPR1 .. EXPR2 : this is true in between where expression EXPR1 is true and expression EXPR2 is true, inclusive.

!m{^\s*-} : not matching a pattern where the line starts with 0 or more whitespace characters followed by a dash.

CodePudding user response：

Using the python PyYaml library, you can use the following script as a filter that removes any section named LaunchPad:

import sys, yaml
data = yaml.safe_load(sys.stdin)
del data['LaunchPad']
yaml.dump(data, sys.stdout)

Simply run: python above-script < input.yml > output.yml

Given this input:

Keypages:
- name: Key pages
LaunchPad:
- name: "\U0001F680Launch Pad"
- location: US
Microservices:
- name: 'Micro services '

The above script produces this output:

Keypages:
- {name: Key pages}
Microservices:
- {name: 'Micro services '}

CodePudding user response：

Using sed

$ sed '/^LaunchPad/,/^[[:alpha:]]/{/^LaunchPad/!{/^-/d};/^LaunchPad/d}' input_file
Keypages:
- name: Key pages
Microservices:
- name: 'Micro services '

/^LaunchPad/,/^[[:alpha:]]/ - Match lines beginning with LaunchPad to the next line beginning with any alphabetical character
/^LaunchPad/! - Ignore lines beginning with LaunchPad
/^-/d - Match lines beginning with a dash then delete them
/^LaunchPad/ - Finally, delete the line beginning with LaunchPad

CodePudding user response：

This might work for you (GNU sed):

sed -n '/^LaunchPad:/{:a;n;/^-/ba};p' file

Turn off implicit printing -n.

Match a line beginning LaunchPad: and then fetch following lines beginning with -.

Print all other lines.

Alternative:

sed '/LaunchPad:/{:a;N;/^-/Ms/\n//;ta;D}' file