This is a continuation of this article. 2-1. Input for becoming a WEB engineer (Linux basics) An article on inputs and their outputs to lay the foundation for Linux. Also, since there is a lot of content, the articles will be posted separately.
As mentioned in the previous article, the teaching materials and environment are as follows. ・ Use Udemy for business as teaching materials. [Can be done in 5 days] Introduction to Linux for the first time (LPIC Level 1 compatible) (Lecturer: Hiroki Inoue) -The Linux environment (Ubuntu) utilizes the EC2 instance of AWS. -Region: Asia Pacific (Tokyo) ap-northeast-1 -AMI：Ubuntu Server 20.04 LTS (HVM), SSD Volume Type -Instance type: t2.micro
Linux is multitasking and multiuser. There is a user account and an account used by the application.
/etc/passwd The format is as follows. ** Username: Password (x): UID: GID: GECOS: Home Directory: Default Shell **
In addition, permission is the access permission permission setting. You can check the permissions with the [ls -la] command.
Since the access authority setting of r, w, x is expressed by 0,1, it can be expressed as follows.
| Access rights | Binary number | Decimal number |
|---|---|---|
| rwx | 111 | 7 |
| rw- | 110 | 6 |
| -w- | 010 | 4 |
| r-x | 101 | 5 |
You can change the owner's settings. For example, the command to make the file owner root is
chown command
sudo chown root:root test.txt
You can set access permissions. For example, the command to give the user write permission is:
chmod command
sudo chmod o+w test.txt
There are three ways to introduce the package.
| Method | Contents |
|---|---|
| apt-get command | Batch execution on the command line |
| Ubuntu Software Center | Batch execution with GUI tool |
| deb file download & dpkg command | Independent download and installation |
The options of the dpkg command are as follows
dpkg command
dpkg [option]dpkg package file.deb
| option | function |
|---|---|
| -i | Installation |
| -r | Uninstall (leave settings) |
| -P | Uninstall (delete settings) |
| -l | View installation packages |
| -L | Display the file list of the installation package |
| -s | Display specified package information |
| -S | Search and display installed files |
| -E | Do not overwrite if it is the same version |
| -G | Do not overwrite if a new version is installed |
The options of the apt-get command are as follows
apt-get command
dpkg [option]d package name
| option | function |
|---|---|
| -i | Installation |
| -r | Uninstall (leave settings) |
| -P | Uninstall (delete settings) |
| -l | View installation packages |
| -L | Display the file list of the installation package |
| -s | Display specified package information |
| -S | Search and display installed files |
There are three ways to introduce the package.
| Method | Contents |
|---|---|
| yum command | Batch execution on the command line |
| Package manager | Batch execution with GUI tool |
| rpm file download & rpm command | Independent download and installation |
The options for the yum command are:
yum command
yum [option]Command package name
| command | function |
|---|---|
| install | Installation |
| remove | Uninstall |
| check-update | View update target list |
| update | Package update |
| list | List of packages |
| repolist | List of registered repositories |
| search keyword | Keyword package search |
You can only download files with the command [yum downloader].
The options of the rpm command are as follows
rpm command
rpm [option]package name.rpm
| option | function |
|---|---|
| -i | Installation |
| -U | Upgrade (install if not) |
| -F | Upgrade (if installed) |
| -h | View progress |
| --force | Force installation |
| --nodeps | Ignore package dependencies |
| -e | Find and view uninstalled files |
| -q | Inquiry |
| -l | View installation files |
| -a | Display of all information |
| -p | Package specification |
| -f | Display the package of the specified file |
You can execute a specified command at a predetermined time.
Display a list of processes to be executed regularly
crontab -e
The format of crontab is here. [Minute, hour, day, Monday, day of the week, execution job]
df command
df [option] [file name]
| df command option | function |
|---|---|
| -i | View inode usage |
| -h | Show M, G |
| -T | Show file system type |
du [option] [Directory file]
| du command option | function |
|---|---|
| -a | Information display of directories and all files |
| -s | Show total only |
| -h | M,Show G |
| option | function |
|---|---|
| fsck.e2fsck | File system check. |
| debugfs | Debug of ext file system |
| dumpe2fs | Information display of ext file system |
| tune2fs | Parameter operation of ext file system |
fsck command
fsck [option]Device file
| option | function |
|---|---|
| -t | File system (ext2,ext3 etc.) |
| -c | Investigate bad blocks when creating a file system |
| -b | Recover by specifying a backup superblock |
| -n | Command execution confirmation (does not process) |
dumpe2fs command
dumpe2fs [option]Device file
| option | function |
|---|---|
| -b | Show bad blocks |
| -h | Display only superblock information |
The backup location of the superblock is as follows.
| Block size | Backup superblock location |
|---|---|
| 1024(1kb) | 8193 |
| 2048(2kb) | 16384 |
| 4096(4kb) | 32768 |
debugfs command
debugfs [option]Device file
| option | function |
|---|---|
| -b | Apply block size |
| -c | Open read-only |
| -R | Executes the specified command, not interactively |
| -n | reading |
debugfs command
debugfs [-R command]Device file
| command | function | command | function |
|---|---|---|---|
| ls | View file list | chroot | Change root directory |
| cat | Display inode information | pwd | Current directory display |
| cd | Change current directory | close | File system closed |
| -n | reading | quit | Exit debugfs |
tune2fs command
tune2fs [option]Device file
| option | function |
|---|---|
| -c times | Number of mounts before executing file system check |
| -i d, m, w | File system check interval d, m, w |
| -j | Added ext3 journal (change history) |
| -I | Display of super block information |
| -L volume name | Give the file system a volume name |
XFS management tool
XFS (Journaling File System),~500TB.CentOS7/Standard with RHEL7)
| tool | function |
|---|---|
| xfsinfo | Display information about the XFS file system |
| xfs_metadump | Save XFS file system metadata to a file |
| xfs_mdrestore | xfs_Restore metadump image |
Quota is the control of the disk space that can be used by the user on linux.
quatacheck command (quote initialization)
edquato [optional] file system
quotaon [option] file system quotaoff [option] file system
repquota command ｜ requota [-a] File system ｜ -a option: For all file systems quota {-u, g}: User group quota setting display
That's the basics of Linux. Next time, I will learn JavaScript
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