Arch Linux has helped me learn and I am grateful.

Question

I am going to tell you what sparked this thread first:  I was reading your wiki on installing a 32bit bundled system into a 64bit system. And NO, I did not know what the heck was going on as usual. The thing is I am always curious. That is why I end up learning. Here is what sparked me...  I got to the 'sed' command and did NOT understand what was going on and I dove in! What a wonderful and amazingly, useful tool. Instead of just copying commands such as:
# sed -e 's/\$arch/i686/g' /etc/pacman.d/mirrorlist > /opt/arch32/mirrorlist
# sed -e 's@/etc/pacman.d/mirrorlist@/opt/arch32/mirrorlist@g' -e '/Architecture/ s,auto,i686,' /etc/pacman.conf > /opt/arch32/pacman.conf
I took the command apart,  tried it in various ways, made test files and learned what it all meant. This type of thing is happening over and over again while using Arch. Arch was extremely overwhelming at first but, I really like it that way, I tend to learn really fast this way. In the beginning it is REALLY hard though.
i have read about said and I know about substitute and global (s///g) but what through me off was -e '/Architecture/ s,auto,i686,' So I made a test file with Architecture in it.
echo "Architecture = auto" > test
then ran
cat test | sed -e '/Architecture/ s,auto,i686,'
Wow! Guys, I was so excited when I finally figured out what was going on. Through trial and error, I just learned some really cool things about said and also got better at seeing that you can use any character as the separator - like @ instead of /. See this makes me happy, when I figure something out like this. It is SO rewarding. Im like a kid at Christmas
So what is happening is I am getting this phenominal understanding of Linux by diving deep into Arch Linux. I have now swithced over my only computer to Arch Linux. I only really cared about a few windows programs and with wine I have one of them running!!
I just want to thank you all for such a great experience. I didn't know how much I love this stuff until I started with Arch Linux. Thanks again!
Last edited by AcousticBruce (2015-05-21 16:21:18)

Answer 1

firekage wrote:
I wanted to learn too...so i have question.
Could somebody explain  this? Also, what this is exacly
'/Architecture/ s,auto,i686,'
Let me show you by example...
echo "hello world" | sed 's/world/universe/'
echo "hello world" | sed 's,world,universe,'
echo "hello world" | sed 's@world@universe@'
Notice all of these are the same result. This is because you can use any character you like in place of the separator.
So when you look at this '/Architecture/ ***s.auto,i686,*** that is replacing the word 'auto' with 'i686'
The /Architecture/ is like using grep.
so if you have a file that looks like this
color1 = red
color2 = red
Easy way to make this in one command. Make sure and use $ and ' ' instead of " "
echo $'color1 = red\ncolor2 = red' > test
and run this
cat test | sed -e '/color1/ s,red,blue,'
same thing...
cat test | sed -e '/color1/ s@red@blue@'
also to prove its like grep
cat test | grep color2 | sed -e 's/red/black/'
sed is very powerful and awesome. There is WAY more than this.
Last edited by AcousticBruce (2015-05-21 18:39:28)