linux grep exclude

In Linux, grep can be used to exclude certain patterns from the search results using the -v option, which inverts the match. Here are some examples of how to use grep to exclude patterns:

1. Exclude a single pattern:
   Search for lines that do not contain the word “error”:

   grep -v 'error' filename

2. Exclude multiple patterns:
   Search for lines that do not contain either “error” or “fatal”:

   grep -v 'error\|fatal' filename

3. Combine exclusion with other patterns:
   Search for lines that contain “warning” but not “info”:

   grep 'warning' filename | grep -v 'info'

4. Exclude a pattern using regular expressions:
   Search for lines that do not end with “error”:

   grep -v 'error$' filename

5. Exclude patterns case-insensitively:
   Search for lines that do not contain “error” in a case-insensitive manner:

   grep -vi 'error' filename

6. Exclude patterns and show line numbers:
   Display line numbers for lines that do not contain “error”:

   grep -vn 'error' filename

7. Exclude multiple patterns with extended regular expressions:
   Use -E to enable extended regular expressions and exclude multiple patterns:

   grep -E -v '(error|fatal)' filename

8. Exclude patterns in a recursive search:
   Search recursively in a directory for lines that do not contain “error”:

   grep -r -v 'error' /path/to/directory

9. Exclude patterns in combination with ls:
   Combine grep with ls to exclude filenames with certain patterns:

   ls -l | grep -v 'pattern_to_exclude'

10. Exclude patterns in a file and search for another pattern:
    First exclude lines with “info” and then search for “warning”:
    bash grep -v 'info' filename | grep 'warning'

The -v option tells grep to select only those lines that do not match the given pattern(s). This is useful when you want to filter out specific content from the results and focus on the lines that do not contain certain words or patterns.