what is the meaning of this Linux command?

Question

I'm little bit new in sql command so please help me to clear this doubt

ps -ef|grep tomcat

Answer 1

This is not a SQL command,it's an unix/linux command check out forum answer below can clear your doubts. https://askubuntu.com/questions/852206/what-does-ps-efgrep-processname-mean

In short : look for lines containing processname in a detailed overview/snapshot of all current processes, and display those lines in linux command prompt environment

Answer 2

ps -ef says list all of the processes. (The -e option means every process, and the -f means use the "full" format in the listing.)

| says pipe the output of the previous command to the next command

grep tomcat say show (i.e. write to output) only those lines in the command's input that contain the string tomcat.

Combined, it means "show me the tomcat processes".

---

The "secret" to understanding a complicated Linux command is:

1. Understand the shell syntax; i.e. how |, <, >, $ and so on work.
2. Break the command line into its commands
3. Look up and read the manual entry for each command.