Uncommenting a config line based on regex with string replace

Question

I have a config file with a bunch of URLs for repos that are commented out. I need to uncomment a specific one and thought sed would make it easy to match a regex then doing a string replace on that line.

I was wondering if my regex in correct for sed syntax or if the sed command is not correct?

mirrorRegex="^# http.*vendor.*distroARCH-1.1\/"
sed '/$mirrorRegex/s/# //' /etc/repos

Before:

# ftp://mirrors.example.com/distro/distroARCH-1.1/
# http://mirrors.example.com/distro/distroARCH-1.1/
# ftp://packages.vendor.org/distro/distro/distroARCH-1.1/
# http://packages.vendor.org/distro/distro/distroARCH-1.1/
# http://mirror.school.edu/pub/distro/distroARCH-1.1/
# http://system.site3.com/distroARCH-1.1/

After: What is expected.

# ftp://mirrors.example.com/distro/distroARCH-1.1/
# http://mirrors.example.com/distro/distroARCH-1.1/
# ftp://packages.vendor.org/distro/distro/distroARCH-1.1/
http://packages.vendor.org/distro/distro/distroARCH-1.1/
# http://mirror.school.edu/pub/distro/distroARCH-1.1/
# http://system.site3.com/distroARCH-1.1/

@UriMikhli the second part is what I expected but it wasn't working anubhava pointed out that I was using single quotes which wasn't expanding the shell variable when sed was ran. — krizzo
– krizzo, Commented Dec 17, 2013 at 20:23

anubhava · Accepted Answer · 2013-12-17 20:20:37Z

4

You need to use double quotes in order to expand shell variables:

sed "/$mirrorRegex/s/# //"

answered Dec 17, 2013 at 20:20

anubhava

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1 Comment

krizzo Over a year ago

Wow I don't know why I didn't remember that. Thank you, don't I feel foolish. I'll accept this as the answer as soon as I can.

Jotne · Accepted Answer · 2013-12-18 06:45:02Z

1

You can use awk like this to do the same:

awk '$0~var {sub(/^# /,x)}1' var="$mirrorRegex" file

answered Dec 18, 2013 at 6:45

Jotne

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krizzo Over a year ago

Awesome thanks for showing me that. I figured awk would work as well I'm trying to learn sed and awk.

NeronLeVelu · Accepted Answer · 2013-12-18 08:15:04Z

0

sed 's|^#[[:blank:]]*\(http.*vendor.*distroARCH-1.1/.*\)|\1|' YourFile

use of other separator than default / (| in this case) will help

and with variable version

Content='http.*vendor.*distroARCH-1.1/'
sed "s|^#[[:blank:]]*\(${Content}.*\)|\1|" YourFile

answered Dec 18, 2013 at 8:15

NeronLeVelu

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