Newly Blog

• crontab -l //list crontab

• crontab -r //remove crontab

• crontab -e //edit crontab

  • minute hour day-of-month month day-of-week cmd
  • each term can be a single number, e.g., 3, or a range, e.g., 3-6, or a set, e.g., 3,5,7, or interval, e.g., */10
  • for example, “ /10 * sh ~/cmd.sh” means executing cmd.sh every 10 minutes.

In windows, the function of contrab can be realized by using “task scheduler”.

Here is a website link to query linux commands.

1. create new user with home folder

   1	adduser XXX

2. sudo privilege: vim /etc/sudoers and add $username ALL=(ALL) ALL at the bottom.

3. start ssh on the server, the default port is 22

   1 2	sudo apt-get install openssh-server sudo/etc/init.d/ssh start

4. list

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   list -a #including hidden files list -S #arrange by size list -t #arrange by time

5. view text

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   cat head/tail -n 10 tmp.txt #view the first/last 10 lines less #more powerful than more

6. Change the privilege

   1 2	chmod 777 ./ chmod a+x ./

7. Check disk or file size

   1 2	df -h du ./ --max-depth 2 -h

8. Compress or uncompress files, refer to this link.

9. Grep + regular expression

   1	grep [xyz]

10. Search file

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    locate "keyword" #fast find ./ -maxdepth 1 -name "*keyword*" find ./ -name "*keyword*" -size +50M -size -100M find ./ -name "*keyword*" -mmin -10 #m:modify min:minute find ./ -name "*keyword*" -exec rm -r {} \;

11. Pipe commands

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    ls -l | tr -s ' ' | cut -d ' ' -f 2 #tr to truncate space ls -l | sort -rnk2 #-r:reverse -n:numerical -k:k-th column ls -l | wc -l #count line

12. xargs:

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    cat python/requirements.txt | xargs -L 1 sudo pip install find . -name "*.c" | xargs rm -rf find . -name '*.c' | xargs grep 'stdlib.h'

13. alias: temporary alias command

    1 2	alias lnew="cd /home/niuli/caffe" unalias lnew

14. export: The export command is one of the bash shell built-in commands, which means it is part of your shell.

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    export a=linux.com echo $a export -n a #remove variable printname () { echo "Linuxcareer.com"; } export -f printname #export function

    add LD_LIBRARY_PATH

    1 2	echo 'export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/cuda/lib64:/usr/local/lib' >> ~/.bashrc source ~/.bashrc

15. shellscript sample

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    #!/bin/bash read -p "Please input your first name: " echo -e "\nYour full name is: $firstname $lastname" test ! -e $filename && echo "The filename '$filename' DO NOT exist" && exit 0 test -f $filename && filetype="regulare file" test -d $filename && filetype="directory" [ "$yn" == "Y" -o "$yn" == "y" ] && echo "OK, continue" && exit 0 if [ "$yn" == "Y" ] || [ "$yn" == "y" ]; then echo "OK, continue" elif [ "$yn" == "N" ] || [ "$yn" == "n" ]; then echo "Oh, interrupt!" else echo "I don't know what your choice is" fi while [ "$yn" != "yes" -a "$yn" != "YES" ] do read -p "Please input yes/YES to stop this program: " yn done for animal in dog cat elephant do echo "There are ${animal}s.... " done

1. zip/unzip

   winrar x -y -ibck zip_file_name unzip_file_name //x means unzip, -y means yes to interrupted queries, -ibck means running in the background

2. generate the file list under one folder

   dir D:\test /b >list.txt or dir D:\test /b >list.xls

3. combine multiple compressed volumes

   copy /b logs.tar.gza* logs.tar.gz

First check whether the file system is MBR+BIOS or GPT+UEFI. Nowadays, most computers are GPT+UEFI, so we only talk about GPT+UEFI here.

1. Download Ubuntu iso and make a U-installer using rufus. When using rufus, notice the option of GPT+UEFI.

2. Start the computer from U-installer. The most important thing is making a proper partition for Ubuntu. At least make three partitions: / (ext4), swap (2G), reserved for UEFI (1G). If necessary, make another partition /home. Note that ubuntu UEFI should be on the same disk as Windows UEFI.

If something is wrong when attempting to enter the BIOS, try the following approaches:

• press F2, F12, ESC, DEL
• change the cable, adaptor, interface, etc (hardware reason)
• update BIOS to the latest version
• for Windows10, settings->recover->firmware
• close fast-boot option in the operation system because fast-boot may directly skip the BIOS stage

Sometimes Ubuntu fails to connect VPN. Open the PPTP advanced options, uncheck EAP and check MPPE.

Server:

1. Install VNC server under Ubuntu: $sudo apt-get install vnc4server

2. Configure the VNC server, $vi ~/.vnc/xstartup
   change the style to gnome-session & in the last line.

3. start the VNC server: $vncserver

Client:

1. Install VNC client under Windows: use http:\IP:580$ID to log in.

Tips: For 10060 error, run $iptables -F to close firewall.

Server:

1. run $sudo apt-get install openssh-server

2. run $ps -A |grep ssh.
   If there is sshd, then ssh-server has been started,
   else run $sudo /etc/init.d/ssh start to start ssh-server.

Tips: To stop ssh-server, execute $sudo /etc/init.d/ssh stop.
To modify the configuration, edit /etc/ssh/sshd_config.

Client:

ssh-client is usually already installed. If not, run
$sudo apt-get install openssh-client.

After installing ssh-client, run $ssh username@192.168.1.112.

Mount Linux folder under Linux

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sudo apt-get install cifs-utils
sudo mount -t cifs -o username=XXX,password=XXX //10.70.1.82/src_dir tgt_dir

Mount Windows folder under Windows

add network device

Mount Linux folder under Windows

1. Install Dokan and WinSSHFS: for Win10, recommend 1.6.1.13 win-sshfs and 1.0.3 Dokan.

2. Open WinSSHFS, fill in the drive name, host, port, username, password, directory. The other entries can be left blank.

Remote Connect to Ubuntu in Windows

a) cmdline: putty, secureCRT

b) window:

xrdp: http://jingyan.baidu.com/article/8ebacdf0cdc64949f75cd555.html

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sudo apt-get install xrdp
sudo apt-get install vnc4server
sudo apt-get install xubuntu-desktop
echo "xfce4-session" >~/.xsession
sudo service xrdp restart

xrdp mm process login response login failed
When this error occurs, try the following methods, followed by “sudo service xrdp restart”.

1. delete vnc processes

   1 2	ps -ef | grep vnc kill -9 XXX

2. delete X sessions, .xrdp, .X11-unix, .X0-20

   1	cd /tmp && ls -a

3. modify “MaxSessions” number

    sudo vim /etc/xrdp/sesman.ini