figure. If you can, please describe this syntax rule and calling sequence in detail. Thank you
.figure code:
-sharp!/bin/bash
function DEBUG()
{
[ "$_DEBUG" == "on" ] && $@ || :
}
for i in {1..10}
do
DEBUG echo $i
done 
figure. If you can, please describe this syntax rule and calling sequence in detail. Thank you
.figure code:
-sharp!/bin/bash
function DEBUG()
{
[ "$_DEBUG" == "on" ] && $@ || :
}
for i in {1..10}
do
DEBUG echo $i
done
["$_ DEBUG" = = "on"] & & $@ | |:This sentence is divided into three parts
["$_ DEBUG" = = "on"] $@ : these three parts are connected in series by & & and | to form cond & & cmd1 | | cmd2 structure.
means that cmd1 is executed when the cond condition is true, otherwise cmd2 .
curl https: packages.gitlab.com g. 2 > dev null | sudo apt-key add-& > dev null I don t know what this statement means. There are numbers > null & >-what all these stand for ...
sincerely ask for advice: < hr > I want to use node as the background to build a video streaming server. The front end is similar to Youku VOD. It can record the playback node function, and load the progress bar at any point (starting from the c...
the original domain name of our company s website has expired. I want to change it to another domain name. How can I change it? The website is developed using Aliyun s Yunmeng. ...
the existing format is as follows: Mon Mar 26 17:43:17 2018 this format is required: 2018-02-21 00:00:00 is there any way to convert it? ...
when using gitlab-ci to build a task, the following error occurs when executing the git clone task or push tried ssh-keyscan-t rsa github.com > > ~ .ssh known_hosts failed after query. there is no problem with manual clone on the server whe...
prompt as follows: Starting nginx: nginx: [emerg] "server " directive is not allowed here in etc nginx nginx.conf:17 what is the reason for this? How to solve it? ...
I need to install both python 2.6 and python 3.6 on my machine. Based on my query, I found that I could use pyenv to do this things, but according to an article I read, python 2 series didn t come with package management tools until python 2.7.9. The...
excuse me: fdisk-l disk dev sda , disk dev mapper centos-root , disk dev mapper centos-swap , disk dev mapper centos-swap these four disks: -sharp fdisk -l dev sda:1000.2 GB, 1000204886016 1953525168 Units = of 1 * 512 = 512 bytes (...
1. Execute npm install-g pm2 2.pm2 pm2 start app.js pm2 3.ln -s root myapp pm2 usr local bin still failed to solve the problem messed up for a long time because no soft connection was created. ln -s root node-v8.9.0-linux-x64 lib node_...
my code is mapped through volumes. I changed the host time today and found that the changed code has no effect. I think it is not timely to update the mapping relationship, resulting in running the old code, changing the time correctly, and working norma...
arp and apr-util installed successfully apache apr-util etc profile but, after trying, it still doesn t work I ve been messing around all day. I d like to ask someone to guide me. Thank you here! ...
docker exec-it-sharp container id bin sh after I enter -sharp how to press delete if I typed the wrong command? Deletion will directly change to ^ H symbol ...
two servers in the same Ali cloud environment A: [root@AY140220152843902sdg46ZsG ~]-sharp openssl version -a OpenSSL 1.0.1e-fips 11 Feb 2013 built on: Wed Mar 22 21:43:28 UTC 2017 although the version is very long, according to built on, there is an ...
packages previously installed globally through npm fail when nvm changes versions cnpm no damn commands can be used, how to solve it? ...
bash-x ...
if a socket between the client and the server is closed (the tcp connection is closed), the client will not be able to re-establish an identical socket in a short period of time (two minutes according to the book). So my understanding is: join me to conn...
Master and Slave built by mysql5.6, the newly created table is not backed up to the slave library master and slvae data can both correspond to can t the test library be automatically backed up to the slave library when establishing a master-slav...
how do I create aliases for btrace applications? ...
ip and port are OK on the server! bind_ip 0.0.0.0 ip ask the boss to have a look. No, no, no. It s okay to pay for an answer! ...
I found it like this update-alternatives --set php usr bin php7.2 the original version is 7. 0 installed. I want to cut the past , but I found that etc php 7.2 is also available here. which is the right way? what else should we pay attention to?! ...