alias
Linux alias command alias command sets.
Users can use alias, alias from a given instruction. If the input alias only, you can list all current aliases settings. Effectiveness alias and only the operation of the sign-in. To each sign is set automatically alias i.e., an instruction may be set in .profile or .cshrc alias.
alias [alias] = [command names]
1.alias displays all current aliases
2.alias [alias] alias represents the display commands
3.alias new command = 'original order'
4.unalias alias alias canceled
chattr
chatter: locked file can not be deleted, can not be changed
+ A: only add content to the file, but not delete,
chattr +a /etc/passwd
-d: can not be deleted
Lock: chattr + i / etc / passwd file can not be deleted, you can not change, can not be moved
View Lock: lsattr / etc / passwd file parameter i represents the addition of a lock
Unlock: chattr -i /home/omd/h.txt - express lift
tail [parameters] [file]
-f read cycle
-q Do not display process information
-v display detailed processing information
Bytes -c <number> displayed
-n <line number> n lines displayed content file tail
--pid = PID with -f combination, indicating the end after the process ID, PID dies
Header -q, --quiet, --silent never given output file name
-s, --sleep-interval = S with the combined -f, it represents the sleep interval repeated every S seconds
Here only remember -f parameter, will be displayed in real-time changes in the log file