Here are some PostgreSQL commands that are similar to \dt, which is used to list all the tables in the current database:

Once a time, I edit a file with vim and save, but a lot of ^M characters was inserted.

To remove ^M characters with vim, I found this solution:

接上一篇 docker 容器安全与 firewalld；为了正常使用docker容器和firewalld，而不修改docker的daemon.json，按如下步骤个性firewalld规则，其本质上是修改ptables规则，修改完成后可以用iptables -nL 查看。

只需结束这个进程就可以：

ps -ef|grep com.apple.quicklook.ThumbnailsAgent 
再kill -9 xxx

之前试过的killall Dock 做多大作用。

Both Parse Server and Realm are popular choices for developing mobile apps. However, the choice between the two depends on your specific requirements and development needs.

Most common short names for Kubernetes resources which was used in command kubectl get:

po or pod: Pods
deploy or deployment: Deployments
svc or service: Services
cm or configmap: ConfigMaps
secret: Secrets
pv or persistentvolume: Persistent Volumes
pvc or persistentvolumeclaim: Persistent Volume Claims
sts or statefulset: StatefulSets
job: Jobs
cronjob: CronJobs

main ps:

Here are the different values that the s, stat and state output specifiers (header "STAT" or "S") will display to describe the state of a process:

D    uninterruptible sleep (usually IO)
I    Idle kernel thread
R    running or runnable (on run queue)
S    interruptible sleep (waiting for an event to complete)
T    stopped by job control signal
t    stopped by debugger during the tracing
W    paging (not valid since the 2.6.xx kernel)
X    dead (should never be seen)
Z    defunct ("zombie") process, terminated but not reaped by its parent

For BSD formats and when the stat keyword is used, additional characters may be displayed:

<    high-priority (not nice to other users)
N    low-priority (nice to other users)
L    has pages locked into memory (for real-time and custom IO)
s    is a session leader
l    is multi-threaded (using CLONE_THREAD, like NPTL pthreads do)
+    is in the foreground process group

用过Xcode的同学可能遇到过这种情况， 有个CoreSimulator目录 /Users/<name>/Library/Developer/CoreSimulator/Devices非常大， 像我的就已经达到二三十G，对于256G的小硬盘来说太占空间了。

这个原因可能是因为不断升级Xcode版本，有些老的Device已经不用了，但是仍占据空间。

可以使用如下命令快速清理已经不能用的Device：

xcrun simctl delete unavailable

浏览器用google play下载三星Internet；

1. 在三星浏览器里打开
   internet://debug/

2. 右下角打开设置，点开最下面的“Debug settings”

3. 点开“Feature variation test”

4. 修改“Sales code”、“Country code”、“Country iso code”到你想要的区。以港区为例，分别在“Other”里填上“TGY”、“Hong Kong”、“HK”

5. 重启浏览器

6. 在浏览器右下脚中打开广告拦截器， 下载ABP ： 到google play中下载三星浏览器专用ABP；

7. 在ABP中更新广告筛选清单，可接受广告选 否，我想禁用可接受广告。完事。

package main

import (
    "fmt"
    "math/rand"
    "time"
)
        
func main() {
    rand.Seed(time.Now().UnixNano())
    min := 10
    max := 30
    fmt.Println(rand.Intn(max - min + 1) + min)
}