how to use | in Linux? give me an example

The | symbol in Linux is called a pipe. It is used to pass the output of one command as input to another command. Here is an example:

# List all files in the current directory and pass the output to the `grep` command to filter files containing "example"
ls -l | grep example

In this example:

• ls -l lists all files in the current directory in long format.
• The | pipe passes the output of ls -l to the grep command.
• grep example filters the output to show only lines that contain the word "example".

root@DyanGong:~/trainingLog# ls -altr
total 44
drwxr-xr-x 2 root root 4096 Nov  1 14:08 1stNov2024
drwxr-xr-x 2 root root 4096 Nov  5 19:37 5thNov2024
-rw-r--r-- 1 root root   28 Nov 27 10:44 hello.sh
drwxr-xr-x 2 root root 4096 Nov 27 17:22 27thNov2024
drwxr-xr-x 2 root root 4096 Nov 28 16:15 28thNov2024
drwxr-xr-x 2 root root 4096 Nov 29 15:18 29thNov2024
-rw-r--r-- 1 root root   34 Dec  4 14:05 hello1.sh
drwxr-xr-x 2 root root 4096 Dec  4 16:53 4thDec2024
drwxr-xr-x 9 root root 4096 Dec  5 09:34 .
drwx------ 8 root root 4096 Dec  5 14:53 ..
drwxr-xr-x 3 root root 4096 Dec  5 15:09 5thDec2024
root@DyanGong:~/trainingLog# ls -l | grep Dec
drwxr-xr-x 2 root root 4096 Dec  4 16:53 4thDec2024
drwxr-xr-x 3 root root 4096 Dec  5 15:09 5thDec2024
-rw-r--r-- 1 root root   34 Dec  4 14:05 hello1.sh