How to grep multiple lines from a file?

How to grep multiple lines from a file?

I would like to grep in order multiple lines of a file. An example of the file originalfile.txt could be: num=12 workers not specified length= 128 Using array element num= 24 workers not specified length= 128 Using array element …… I want to grep only valuable lines like all those with num and length:

Where can I find the output of grep?

The output will return results from all files the grep command found in the /var/log/ directory and its subdirectories. In this tutorial, you learned how to use grep to search multiple words or string patterns in a file.

How to redirect grep to an output file?

grep -n “test” * | grep -v “mytest” > output-file will match all the lines that have the string “test” except the lines that match the string “mytest” (that’s the switch -v) – and will redirect the result to an output file. Redirection of program output is performed by the shell.

Can you use grep to search multiple strings?

You can grep multiple strings in different files and directories. The tool prints all lines that contain the words you specify as a search pattern. In this guide, we will show you how to use grep to search multiple words or string patterns.

How to grep rows that have certain value in a specific column?

The OP is wanting to use grep, which will print the whole line when a match is found, so the only thing to do is create the pattern that matches all and only what is required. Simplicity itself, and no reason to use sed or awk as `grep can handle the source as a file or a pipe.

How to use grep on column in AWK?

Here I want to only grep the pattern ST in 2nd column. How to do this ? Without doing some fancy RegEx where you count commas, you’re better off using awk for this problem. The -F, parameter specifies the delimiter, which is set to a comma for your data. $2 refers to the second column, which is what you want to match on.

How to grep on a set of files?

If it is simpler, you can just specify each file one after the other. If you need to grep on a arbitrary set of file names that cannot be retrieved by a regular expression:

How to find common lines in two files?

Use comm -12 file1 file2 to get common lines in both files. You may also needs your file to be sorted to comm to work as expected. From man comm: Or using grep command you need to add -x option to match the whole line as a matching pattern.

What does the grep symbol mean in regex?

This means lines that start with an = and no variable name will not be matched. Grep allows for regex matching. We can use a regex match with an “or” statement to search for multiple matches. the | symbol means “or” in regex. Because this is bash we need to escape the | so it becomes \\|