Linux learning day4

http://man.linuxde.net/ // Linux command Daquan
[process management]
1.ps aux: view all currently running processes
USER PID% CPU
user process number when executing the command cpu
% MEM
memory occupied by the process
VSZ RSS TTY STAT START
virtual memory set resident memory set terminal number process status start date
2.ps -ef: view all currently running processes, with parent process number
ps aux | grep process name: view a process status
3.top: dynamic View process
shift + </> view up or down.
Press and hold q on the keyboard to exit
4.kill: send signal
kill -l: produce signal list
kill -9 process number // kill process
kill signal option process pid: send to specified process A number
[compress and decompress files under Linux]

1. gzip – gunzip
   features: only a single file can be compressed, no archive function, the source file does not exist after compression and decompression The
   suffix is ​​.gz
   gzip The file to be compressed
   2. bzip2 – bunzip2
      features: only a single file can be compressed, no archive function, the source file does not exist after compression and decompression The
      suffix is ​​.bz2
      bzip2 The file to be compressed
   3. zip – unzip
      features: with archive function, the source file exists after compression and decompression The
      suffix is ​​.zip
      zip The file to be compressed
   4. tar
      tar -cjf Compressed package name file to be compressed: compressed in
      zip2 format tar -czf Compressed package name file to be compressed: compressed in gzip format
      tar -xvf Compressed package name: decompressed
      Note: j / z needs to be in front of f
      Features: With archive function, source files exist after compression and decompression

Switch Chinese:
search ibus in dash home, run, CTRL + space switch

[Service] tftp
simple file transfer protocol UDP protocol used between the client server-based
tftp service

1. Introduction: The network protocol is mainly used for file transmission in embedded development
2. Operation steps:
   1) Check whether tftp
   sudo dpkg -s tftpd-hpa tftp-hpa
   is installed in the system 2) If tftp is not installed in the system, you need to perform the following operations: if it has been installed, you can directly proceed to the next step
   sudo apt-get install tftpd- hpa tftp-hpa
   3) Modify the configuration file
   sudo vi / etc / default / tftpd-hpa
   Modify the file content to:
   TFTP_USERNAME = “tftp”
   TFTP_DIRECTORY = "/ tftpboot"
   TFTP_ADDRESS = “0.0.0.0:69”
   TFTP_OPTIONS = "-l- s -c "
   4) Create a folder and modify permissions
   sudo mkdir / tftpboot
   sudo chmod 777 / tftpboot
   5) Restart the tftp service
   sudo service tftpd-hpa restart
   6) How to use it?
   linux @ ubuntu: ~ $ tftp ip address (can be local ip address: 127.0.0.1, or other host ip address)
   server and client must be under the same local area network
   tftp> put file name: upload file
   tftp> get file Name: download file
   tftp> q: exit
   Note: to upload files to the under / tftpboot, downloaded from the / tftpboot file to the current path
   may occur problems?
   1. The
      reason for timed out (timeout) is: the above steps are not operated correctly, follow the steps again