bash: command types and commands

• user
  • sudo <command> <arguments>: to work as root user
• Terminal 
  • echo
  • printf
• System and Env
  • pgrep <command name>: to get command process
    • /proc/$PID/environ: process <PID>‘s environment  

• echo
  • echo -e "<string with regexp>"

  • $ echo -e "1\t2\t3"
    > 1    2    3

• printf
  • %s, %c, %d, %f
  • -: left justifying

  • $ printf "%-5s %-5s %-5s\n" This is test
    > This  is    test
    

• <process>

  • $ pgrep bash
    > 8111
    $ cat /proc/8111/environ
    > USER=aaaHOME=/u/aaaPATH=/bin......
    $cat /proc/8111/environ|tr ‘\0‘ ‘\n‘
    > USER=aaa
    HOME=/u/aaa
    PATH=/bin
    ....
    

     

  • sss
  • sss

bash: command types and commands

原文：https://www.cnblogs.com/cc-2020/p/13782478.html