4sync

protected] ~]# Last-n 5Kiosk pts/0:0 Wed Nov 9 19:46 still logged inKiosk pts/0:0 Wed Nov 9 18:57-19:46 (00:48)kiosk:0:0 Wed Nov 9 18:57 still logged inReboot system boot 3.10.0-327.el7.x Thu Nov 10 02:56-19:59 ( -6:-57)kiosk:0:0 Wed Nov 9 17:55-17:55 (00:00)Wtmp begins Wed Sep 28 00:38:05 2016[[email protected] ~]# Last-n 5 | awk ' {print $ ' \ t ' $} 'kiosk:0kiosk:0kiosk:0Reboot bootkiosk:0$ A represents a whole row of dataBuilt-in variablesNF total number of fields per row ($)NR current awk

Priority of the thread:The priority of the thread is divided into three types, namely:1-min_priority10-max_priority5-norm_priorityIf nothing is set the default value is 5The priority of a thread can affect the order in which threads are executed, and of course this refers to a possible impact that does not necessarily affect it. In the default state (for example, the main thread) its default value is 5Specific Code Demo:Package Com.yeqc.thread;class ThRun implements runnable{@Overridepublic void

) {}//return; to } + - voiddoWork () {...} the}Implementation principleThe Countdownlatch is based on the AQS implementation, using the synchronization state of Aqs to represent the counter count.Let's take a look at the implementation of Countdownlatch's inner class Syns:1 Private Static Final classSyncextendsAbstractqueuedsynchronizer {2 Private Static Final LongSerialversionuid = 4982264981922014374L;3 4Sync (intcount) {5SetState (coun

. 1, CacheItem The CacheItem type is used to represent a separate cache entry, the source code is shown below, each field is clearly understandable, and a slightly longer note has been annotated in Chinese. 1//cacheitemisanindividualcacheitem 2//parameterdata Containstheuser-setvalueinthecache. 3typecacheitemstruct{4sync. Rwmutex 5 6//theitem ' Skey. 7keyinterface{} 8//theitem ' Sdata. 9datainterface{}10//"Time to live after not being accessed" 11 /

directly in the program defined variables)[[email protected] ~]# awk-v Test=armo ' begin{print test} ' armo[[email protected] ~]# awk ' begin{test= ' Armo ';p rint test} ' Armo3, the use of built-in variables: NR: Display line number[Email protected] ~]# Tail-n 5/etc/passwd | Awk-f: ' {print nr,$1,$2} ' 1 pulse x2 sshd x3 tcpdump x4 Armo x5 named X[[email protected] ~]#4. Formatted output of printf[[emailprotected]~]#awk-f: ' {printf ("%s,%s\n", $1,$2)} ' /etc/passwdroot , xbin,xdaemon,xadm,xlp

Cut action and usage:Cut [-option] file nameCut-remove sections from all line of filesCut a piece of content from each line of a file-D: Specify the field delimiter, the default delimiter is a space-F: Specify the fields to display-f1,3 showing 1 and 3 segments-f1-3 Show from 1 to 3 segments, i.e.[Email protected] test]# cut-d:-f1,3/etc/passwdroot:0Bin:1Daemon:2Adm:3Lp:4Sync:5Shutdown:6[Email protected] test]# cut-d:-f1-3/etc/passwdroot:x:0Bin:x:1Daem

Linux Command cut usageCut commandCut [OPTION] ... [FILE] ...-D DELIMITER: Indicates delimiter-F Fileds:#: Section # Fields#,#[,#] Discrete multiple fields, such as 1,3,6#-#连续的多个字段, e.g. 1-6Mixed use 1-3,7--output-delimiter=string[[emailprotected]~]# cut-d:-f1/etc/passwd rootbin daemon admlp sync shutdown haltmail uucp operatorgames gopher ftpnobody dbus usbmuxd vcsartkit avahi-autoipd abrt haldaemongdm ntpapache saslauth postfix pulsesshd tcpdump hadoopzhangshan [[emailprotected]~]# cut-d