Command

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general command

eval command


This is equivalent to running the command ls -l directly on the command line.

x="ls -l"
eval $x

source command


source command is used to execute commands from a script file in the current shell environment, rather than starting a new shell, so any changes made to the environment will persist after the script is finished running.

source myscript.sh

similar ways to execute shell script file:

  • sh scriptname.sh : This method will run the script regardless of the user's default shell
  • bash scriptname.sh : This command runs the script using the bash shell
  • ./scriptname.sh : need to provide executed permission for the script (chmod +x scriptname.sh)
  • ./scriptname : if the script has execute permission and it has the appropriate shebang line, you can run it just by typing its name

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mac os


  • open -a application: open app on mac by terminal
  • lauchctl [stop|list]: stop or list out all running services

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networking


  • netstat -a: list down all listening port
  • telnet [ip:port]: ping ip with specified port

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