Linux grep query results are filtered

grep query filtering requires the use of the pipe command |.

For example: 1. The command to find a specific process in the process table is usually as follows:

When output, not only the process data that will be looked for is output, but the data that includes the grep process itself is emptied, because the lookup string is included in the grep call. The methods of filtering grep itself are:

v: ignores grep itself.

2. There is another way:

The string you're looking for becomes a regular expression.

Because the entry for the grep process shows that the processing command takes precedence over the regular expression ([s]ome string). When the grep command is run, the grep process's own entries don't match and are not included in the output.

Use egrep to find multiple strings at once:

In addition, because your current command will be displayed when you ps aux, grep opclient will filter out two records, and then use grep -v grep to filter out the current command, and only the command you want will remain.

You use this command.

pid= pgrep opcclient can be replaced, no need to be so troublesome!

After adding, I can't find it, it may be that there is no process.,Didn't add it.,It's the process ID of your current command that was found.

A common command method for Linux to find the contents of a file.

1. Find the line that matches the specified string from the file content

grep "The string being looked"Filename.

Example: Look for the first level folder in the current directory that contains the specified string. in file.

grep "thermcontact" *in

2. Find the line that matches the regular expression from the content of the file:

grep e "regular expression" filename.

3. The manuscript check letter is not case-sensitive

grep –i "The string being looked"Filename.

4. Find the number of matching rows:

grep -c "The string being looked"Filename.

5. Find the line from the file content that does not match the specified string

grep –v "The string being looked"Filename.

6. Start from the root directory and look for all extensions. log and find the line that contains "error".

find / type f -name "*log" |xargs grep "error"

find . name "*in" |xargs grep "thermcontact"