Ubuntu – grep command for a text file in multiple directories

command linegreptext processing

I have 24 directories in a specific directory (main_directory). Each 24 directory have a text file whose name is DATA.txt.

I need to use grep command to extract below specific pattern for each text file;

2* x  = 3800689.6402     y  = 882077.3636     z  = 5028791.2953

2* x = part is constant for all DATA.txt. The other numeric numbers are variable. I need to extract above line for each DATA.txt and save them into another text file. Which script I can use for this process?

Best Answer

To recursively search using grep, use the -R option.

To search for an exact string, use -F, so that 2* isn't treated as a regular expression.

To search only on specific filenames, use the --include option. Combined:

grep -FR --include=DATA.txt '2* x' main_directory > another_text_file

Related Solutions

Ubuntu – How to use the grep command to extract line which is the next line of greping line

You can use grep -A1 'expression'

From the manual:

-A num
--after-context=num
    Print num lines of trailing context after matching lines.

In your case:

grep -A1 "!        lat" foo | grep -v "!        lat"

should work to extract the second line only.

Note:
You can use grep -P '^! {8}lat' instead of typing many . This is less error prone. The -P flag enables perl style regular expressions and {8} (There is a space before the '{') matches exactly 8 spaces.

Best Answer

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Ubuntu – How to use the grep command to extract line which is the next line of greping line

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