[Linux]Ubuntu/Redhat or CentOS 常用命令

linux ubuntu bash command

1. System commands

2. System tools

1. vi/vim

2. dpkg (Ubuntu)

3. grep

4. samba

samba is for sharing files: build a server, etc.

https://www.tecmint.com/setup-samba-file-sharing-for-linux-windows-clients/

1. Installation

yum update && yum install samba samba-client samba-common cifs-utils

2. Configuration

We add a folder to share, create a group and a user for sharing at system level. So, at last, because we grant rwx to the owner group, which is share, and not to other users(because 777 is not safe!), so we must make sure that the user belongs to group share.

groupadd share                      # add a group share
useradd win7                        # add a user win7
usermod -a -G share win7            # add win7 to group share
mkdir /shareroot                    # create dir /shareroot
chmod 0770 /shareroot               # assign permission to user and group
chgrp share /shareroot              # change the group of /shareroot to share

3. Security

If we have SELinux and Firewall, we must do:

setsebool -P samba_export_all_ro=1 samba_export_all_rw=1
getsebool –a | grep samba_export
semanage fcontext –at samba_share_t "/share(/.*)?"
restorecon /finance
firewall-cmd --permanent --add-service=samba
firewall-cmd --reload

4. Samba config

Open /etc/samba/smb.conf, and add this part:

[share]                             # the name of share
comment=A simple description        # whatever
browsable=yes                       # whether the dir is browseable
path=/shareroot                     # the dir to share. BETTER CREATE IT UNDER ROOT DIR!!!! to avoid permission problem (I created another under /home/westerngun/share and it doesn't work.)
public=no                           # if is public, does not need auth
valid users=@share                  # here @share means group. You can add samba user name like "user1, user2, ..."
writeable=yes
# keep it simple, no more!

After that, run testparm to test each section of samba config. Press Enter to get a dump(the parsing result of samba, i.e., how samba understands the file).

5. Create samba user

smbpasswd -a username add a user to samba database. The user must be created beforehand. And set password. For example:

smbpasswd -a win7
... (password)

The name should be the same as the newly added user.

At last, restart samba service with:

systemctl restart smb

6. Connect to share

In linux:

smbclient -L <ip> -U <username>

To mount it, you can do:

mount //ip/shareroot /media/samba/ -o username=win7

, if /media/samba exists.

To connect from Windows, we can map a net drive, or connect it in the address bar in the file explorer.

Enter "My Computer", choose "Map network drive". Choose a letter, enter the address:

\\192.168.85.128\share

Here we must use the share's name share, not the dir name shareroot.

Enter win7 as username and its password, you are done!

If we pass file from windows to samba share, the file belongs to win7.

7. Misc

7.1 Samba Usermap file

https://www.samba.org/samba/docs/man/manpages-3/smb.conf.5.html#USERNAMEMAP

If you want to map Windows user name to Linux user name, you must edit smb.conf:

[global]
username map = </path/to/some/file>
...

In the file:

<linux_username>=<windows_machine_name\username>

7.2 List samba users

sudo pdbedit -L -v to list all samba users. Use sudo.

7.3 Check share status

smbstatus checks how many shares are and their status.

7.4 Check which window manager you are using (CentOS or Ubuntu)

Use env to check system environment variables, and look for these two:

• XDG_CURRENT_DESKTOP - Tells you what Windows Manager you are using
• GDMSESSION - Tells you what option you selected from the lightdm greeter to login.

https://askubuntu.com/questions/72549/how-to-determine-which-window-manager-is-running#answer-72581

8. change host name

`/etc/sysconfig/network

NETWORKING=yes
HOSTNAME=new-name

Then:

hostname new-name

and reboot.
...and it does not work!

The correct way is:

hostnamectl set-hostname new-name
reboot

3. 快捷键

3. Other tools

Note:
p12 keys cannot be imported into java keystore, because it contains both private key and public key, but .crt only contains public key and can be imported into java keystore directly.

p12 or pks must be converted to .pem by OpenSSL, or by Internet Explorer. More info here.

When exporting from IE, we can choose contains private key and choose a password to protect it. If it has private key, it's exported as .pfx, if not, as .cer. When importing, you can also choose to import private key and public key, or only public key. If only the public key is imported, later it can be exported only as .crt. By default, for security reasons, it's imported only with public key. More info here.

4. All the concurrent paths