简单的bash脚本，我怎样才能让它更短更好？

Question

I wanna a bash command to move to a directory, and then show 2 files' content for each entry, I made this script:

cd /sys/class/net
for i in *; do echo $i; cat $i/{address,operstate}; done

is there anyway to do shorter and better?

Answer 1

No need for the cd . Try the following:

for i in /sys/class/net/*; do echo "${i##/*/}:"; cat $i/{address,operstate}; done

This should give you an output like this:

eth2: 
0f:ed:37:1f:6c:c7
up
lo: 
00:00:00:00:00:00
unknown
wlan0: 
94:58:29:b6:07:3e
down

The echo above removes the leading path elements using bash parameter substitution to make the output prettier.

Answer 2

grep and sort can give a similar answer

(cd /sys/class/net/;grep -T '' */{addre,o}*|sort)

Example output

eth0/address   :10:9a:dd:6e:66:33
eth0/operstate :down
lo/address     :00:00:00:00:00:00
lo/operstate   :unknown
wlan0/address  :e0:f8:47:20:b3:92
wlan0/operstate:up

I really liked the answer using tail, but unfortunately it keep the address and operstate next to each other. Using grep, I can fix this with sort. But it's not one command, sorry.

The -T option to grep does the aligning (using a tab)

Answer 3

I just found tail can do simpler,

 tail /sys/class/net/*/{address,operstate}

this is only one command, without pips and compound shell statements. :) – fluter just now edit