The second wave of orders is coming to us: start-up process, PATH, filter level directory, CD parameters, LS-LRT, command cut logs
1.1
Linux boot- up process 1.1.1
Post (Bios)--MBRBoot--GRUBMenu-- Load Kernel (Kernel)-- RunINITProcess-- Read/etc/inittabconfiguration file-- Execution/etc/rc.sysinitScripts (init scripts, such as settingsIP,hostname)-- Execution/ETC/RC.D/RC(software that is powered on at run level) script-- Start/sbin/mingettyprocess (Display login interface)
1.2
What is
PATH environment variable, what role does it have? 1.2.1
View
PATH environment variable
[Email protected] ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin
1.2.2
PATH function:
1) Environment variables
2) The location of the command is stored
1.2.3
the process of executing a command?
1)ls or mkdir
2) The system will go inside the PATH to find out if the command exists
3) exist on the run
4) Error if not present: Command notfound or no Sush file or directory
1.3
How to filter out the first level directory under the/oldboy directory?
method One: [Email protected] oldboy]# TREE-DL 1
.
├──ext
├──test
├──xiaodong
├──xiaofan
└──xingfujie
Note: 1.-D directory-L equivalent to--level, display up to several levels of directories
Method Two: [Email protected] oldboy]# find-maxdepth 1-type d! -name "."
Note: 1. MaxDepth Deepest
2.! To take the opposite meaning
Method Three: [Email protected] oldboy]# ls-l |grep "^d"
Drwxr-xr-x. 3 root root 4096 Dec 10:35 ext
Drwxr-xr-x. 2 root root 4096 Dec 10:35 test
Note: Find the line that starts with D, the ^ number is used only by three Musketeers, and the regular expression is ... Line starting with
method Four: [Email protected] oldboy]# Ls-l | awk ' $2>1 '
Note:The second line is a $ =
Method Five: [Email protected] oldboy]# ls-f |grep "/"
ext/
test/
Note: -F adds different tags (tails) to different files
1.4
use of the CD command and its options
Note: The CD is an internal command and can be viewed in the manual using man cd or help CD
1.4.1
CD-
[Email protected] oldboy]# CD-
Note: Quickly go back to where you were last
1.4.2
CD.
[[Email protected]/]# CD.
Note: Indicates the current directory
1.4.3
CD..
[Email protected]/]# CD.
Note : Return to the top level directory
1.4.4
CD ~
[Email protected]/]# CD ~
[[Email protected]/]# CD
Note: Enter the current user's host directory, and CD a role
1.5
To View the Help manual:
1)helpCD view internal commands
2)ls--help view external command
3)mancd view full help
Note: Chinese man manual (man.linuxde.net)http://linux.51yip.com/ http://man.linuxde.net/
1.6
how the LS command is displayed in chronological order 1.6.1
When LS is displayed in chronological order
Note: The default is a-Z display
[Email protected] oldboy]# LS-LT
Note:-T is displayed according to the modified time of the file (most recent file on top)
1.6.2
ls displayed in reverse order of time
[Email protected] oldboy]# LS-LRT
Note:-r Displays content in reverse order (including time, letters), latest files at the bottom
1.6.3
ls According to the time of the year/ month / day / hour / minute / display
[Email protected] oldboy]# ls-l--time-style=long-iso
-rw-r--r--. 1 root root 0 2017-12-12 123.txt
1.7
To cut a log by command
Note: You can alsoMonitor the log by software, monitor the size of disk space, etc.1.7.1
Modify the system time
[[email protected] oldboy]# date-s "2017-12-19 11:01:00"
1.7.2
the access log for the Nginx/apache service is logged by day in the server local directory /app/logs/ , which is most required to keep The access log for the last 7 days, how can I resolve it? ( Replace rmwith ls-l first)
1) show Log for 7 days (7)
[Email protected] logs]# Find-type f-mtime 7
2) display logs for the last 7 days (-7)
[Email protected] logs]# find-type f-mtime-7 |xargs ls-l
3) display logs up to 7 days ago (+7)
[Email protected] logs]# find-type f-mtime +7 |xargs ls-l
1.7.3
Find the/aap/logs below with . Log and the modified time is 7 days before the file is deleted (first with ls-l instead)
To create a running environment:
Mkdir-p/app/logs
Cd/app/logs
For time in {01..20};d o date-s "201705$time"; Touch access_www_$ (date +%f). Log;d One
Date-s "20170520"
Workaround:
method One: [Email protected] logs]# Find-type f-mtime +7-exec ls-l {} \;
Method Two: [Email protected] logs]# find-type f-mtime +7 |xargs ls-l
Method Three: [[email protected] logs]# ls-l $ (find-type f-mtime +7)
1.7.4
Debug System service Yes, want to see the/vat/log/secure system Log update in real time, how to do?
[Email protected] logs]# tail-f/var/log/secure
Note:tail-f displays end-of-file updates in real time
1.7.5
Find All files under/oldboy that are larger than 1M at the end of log Copy to / tmp .
method One: [[email protected]/]# CP $ (find/oldboy-type f-size +1024k-name "*.log")/tmp/
Method Two: [Email protected]/]# find/oldboy-type f-size +1024k-name "*.log"-exec cp {}/tmp/\;
Method Three: [Email protected]/]# find/oldboy-type f-size +1024k-name "*.log" |xargs cp-t/tmp/
Note : cp-t reverse copy, put the files to be copied on the last side (normal situation in front)
1.7.6
Merge 2 or more file sizes together
[Email protected] logs]# cat/etc/services/etc/services >/123.log
Note:Cat full name is concatenate, merging the meaning of the associated
Linux boot process, PATH, filter level directory, CD parameters, LS-LRT, command cut logs