How do I pair every two lines of a text file with Bash? [duplicate]

问题

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How to merge every two lines into one from the command line? (20 answers)

Closed 3 years ago.

With a simple bash script I generate a text file with many lines like this:

192.168.1.1
hostname1
192.168.1.2
hostname2
192.168.1.3
hostname3

Now I want to reformat this file so it looks like this:

192.168.1.1 hostname1
192.168.1.2 hostname2
192.168.1.3 hostname3

How would I reformat it this way? Perhaps sed?

回答1:

$ sed '$!N;s/\n/ /' infile
192.168.1.1 hostname1
192.168.1.2 hostname2
192.168.1.3 hostname3

回答2:

Here's a shell-only alternative:

while read first; do read second; echo "$first $second"; done

回答3:

I love the simplicity of this solution

cat infile | paste -sd ' \n'

192.168.1.1 hostname1
192.168.1.2 hostname2
192.168.1.3 hostname3

or make it comma separated instead of space separated

cat infile | paste -sd ',\n'

and if your input file had a third line like timestamp

192.168.1.1
hostname1
14423289909
192.168.1.2
hostname2
14423289910
192.168.1.3
hostname3
14423289911

then the only change is to add another space in to the delimiter list

cat infile | paste -sd '  \n'

192.168.1.1 hostname1 14423289909
192.168.1.2 hostname2 14423289910
192.168.1.3 hostname3 14423289911

来源：https://stackoverflow.com/questions/1513861/how-do-i-pair-every-two-lines-of-a-text-file-with-bash