Grep a word out of a file and save the file as that word

Question

I am using Ubuntu Linux and grepping info out of a file (lets say filename.log) and want to save the file using some of the info inside of (filename.log).

example:

The info in the (filename.log) has version_name and date.

When displaying this info on screen using cat it will display:

version_name=NAME
date=TODAY

I then want to save the file as NAME-TODAY.log and have no idea how to do this.

Any help will be appreciated

Answer 1

You can chain a bunch of basic linux commands with the pipe character | . Combined with a thing called command substitution (taking the output of a complex command, to use in another command. syntax: $(your command) ) you can achieve what you want to do.

This is what I came up with, based on your question:

cp filename.log $(grep -E "(version_name=)|(date=)" filename.log | cut -f 2 -d = | tr '\n' '-' | rev | cut -c 2- | rev).log

So here I used cp , $() , grep , cut , tr and finally rev .

Since you said you had no idea where to start, let me walk you trough this oneliner:

1. cp - it is used to copy the filename.log file to a new file, with the name based on the values of version_name and date (step 2 and up)
2. command substitution $() the entire command between the round brackets is 'resolved' before finishing the cp command in step 1. eg in your example it would be NAME-TODAY. notice the .log at the end outside of the round brackets to give it a proper file extension. The output of this command in your example will be NAME-TODAY.log
3. grep -E "(version_name=)|(date=)" grep with regexp flag -E to be able to do what we are doing. Matches any lines that contain version_name= OR date= . The expected output is:

version_name=NAME
date=TODAY

5. cut -f 2 -d = because I am not interested in version_name , but instead in the value associated with that field, I use cut to split the line at the equals character = with the flag -d = . I then select the value behind the equals character (the second field) with the flag -f 2 . The expected output is:

NAME
TODAY

6. tr '\\n' '-' because grep outputs on multiple lines, I want to remove all new lines and replace them with a dash. Expected output:

NAME-TODAY-

7. rev | cut -c 2- | rev rev | cut -c 2- | rev I am grouping these. rev reverses the word I have created. with cut -c 2- I cut away all characters starting from the second character of the reversed word. This is required because I replaced new lines with dashes and this means I now have NAME-TODAY- . Basicly this is just an extra step to remove the last dash. See expected outputs of each step:

-YADOT-EMAN

YADOT-EMAN

NAME-TODAY

remember this value is in the command substituion of step 2, so the end result will be:

cp filename.log NAME-TODAY.log

Answer 2

我设法通过执行以下操作来解决此问题： grep filename.log > /tmp/file.info && filename=$(echo $(grep "version_name" /tmp/filename.info | cut -d " " -f 3)- $(grep "date" /tmp/filename.info | cut -d " " -f 3)-$filename.log