Linux and Shell Learning

sudo spctl--master-disable open application from any source when installed;

sudo lsof-i:9000;sodu kill-9 pid; View port occupancy and kill process;

The Rmic compiler generates stub classes and skeleton classes;

/home Install software

• Boot of the kernel
  • /boot
• Run Init
  • SysV: init, before CentOS 5, configuration file:/etc/inittab.
  • Upstart: init,centos 6, configuration file:/etc/inittab,/etc/init/*.conf.
  • Systemd: Systemd, CentOS 7, configuration file:/usr/lib/systemd/system,/etc/systemd/system.
    • Daemon
    • RunLevel
• System initialization
• Set up terminal
• User Login System
• System directory Structure
  • /bin common command/boot link mirror/dev external device/etc System Management/home directory/lib dynamic connection shared library
  • /lost+found illegal shutdown/media External device Mount/mnt temporary media/opt software/proc memory/root Super Permissions home Directory
  • /sbin hypervisor/selinux Firewall/srv service data/sys (proc+devfs+devpts)/tmp Temporary
  • /usr (program Files)/usr/bin\sbin (Bin and sbin)/usr/src kernel source code. /VAR (variable)
    • 3s-e-single-passwd
• Telnet securecrt,putty,ssh Secure shell;ssh-p (port)
• File properties
• ll or Ls-l
• D Directory-File L link B can be random access device C disposable reading device
• Chgrp-r recursive owner Grouper/chown-r owner:grouper filer/chmod-r xyz filer (X1R2W4)/
• chmod o/g/u/a (comma interval) +-= xrw file
• Cat
• nl
• Tac
• More/less
• Useradd-c comment-d dir-g group-g apgroup-s shelldir (-u-o) [etc/passwd ...] [Userconf]
• Userdel-r Name
• Usermod (useradd command) name
• Passwd-l lock-u unlock-d dis-f first-next
• Groupadd-g Gid-o/groupdel/groupmod
• NEWGRP Name
• /etc/(Passwd,shadow,group)
• nweusers< (txt written in passwd format);passwd< (txt in name:pwd format)
• Pwunconv Cancel Shadow Password;pwconv enable Shadow password
• DF (File system usage) du (disk space usage) fdisk (partition)
• Shell
  • Suffix can be changed casually
  • $ (#var) length $ (var:startInd:endInd) intercept ' expr index ' ${var} ' var_s ' Lookup
  • Array variable values are separated by spaces or newline var[@] get array all elements (var[*] should also be possible)
  • #var删除左起至第一var%var Delete right up to first Var # #删除左起至最后var%%var Delete right up to last Var
  • Var=holyshit ${var:7}=t ${var:1-2:3}=t (on the right) $ (the last position in the var:1-2}=t string is 0 The first one is 1; or the last position is-1
  • For i in "[email protected]";d o
    • Echo $i
  • Done
  • + - * / % = == !=
  • -eq-lt-gt-ge-le-ne
  • ! -o-a
  • && | |
  • = (there are spaces)! =-z-n Str ([var]) This was about the characters operation.
  • -E (exit)-S ()-X (excutable)-W (writable)-R (readable)-f (file?)-D (dir?)
  • ECHO-E Open Escape "" to use text format directly
  • Test is bound with []
  • file contains. File/source file
  • redirect >> output append;

Linux and Shell Learning