sed：如何在文本块后插入行？

Question

I have text file: file.conf

### Option: LogFile
#       Name of log file.
#       If not set, syslog is used.
#
# Mandatory: no
# Default:
# LogFile=

### Option: LogFileSize
#       Maximum size of log file in MB.
#       0 - disable automatic log rotation.
#
# Mandatory: no
# Range: 0-1024
# Default:
# LogFileSize=1

And I have tried:

sed --posix -e '/\bLogFile\b/{:a;n;/^ *$/!ba;i\LogFile=/tmp/log1.log' -e '}' file.conf

And this is working fine, for those option block which is followed by a blank line.

Problem with this is: at the end of last block if no new line is present, then it dose not insert the line. Here with text LogFileSize.

How to handle this.

Answer 1

1. To add after match line:

    $ sed '/#.*LogFile=/a\\LogFile=/tmp/log1.log' 1.cat 

   will do:

    # LogFile= LogFile=/tmp/log1.log 

2. To add before first empty line:

    $ sed '/^$/i\\LogFile=/tmp/log1.log' 1.cat 

   will do:

    # LogFileSize=1 LogFile=/tmp/log1.log