Miscellaneous Shell History (1)

File creation related

• touch: Create file

• mkdir: Create folder

• chmod: Set file permissions

• chown: Set file owner

• mv: Move and rename files

Check file information

• -rwxr-xr-x Part: Checking the file's permissions

1. the first digit means File Type (-, d, l)
2. read-write-execute permissions are expressed in 3-digit form for user, group, and others, The value of rwx can be changed to 7 and -xr can be changed to 4 because r has a value of 4, w has a value of 2, and x has a value of 1 in the form of a binary number.

chmod 744 Slack.lnk

This type of command can be used to set permissions. 3. Number of links (where 1 is written) 4. Information about the owner (blank) and ownership group (197609) 5. File size 6. Information about the last modified time 7. The file name

ssh-keygen

• Used in many cases for Git authentication via Secure Shell public key

• Included in Window and Linux packages

• When generating a key, a key and .pub file is generated, which is used as a key-lock by providing the contents of the .pub file to the server

How to adjust the capacity of a file in the shell

mkfile -n 10k test.sh
fallocate -l 10k test.sh
truncate -s 10k test.sh

You can resize an existing file or create a new file with this command.

Change the file modification history

touch -t 2301011234 timefile.sh

Command to change the modification history of a file to show that it was last modified on 1/1/23/12:34 as an application of touch.

Hard Link & Symbolic Link

Symbolic Link (Soft Link)

A link that makes the original file available in a specific folder, such as a shortcut in Windows, and does not work if the original is deleted.

Hard Link

Unlike a symbolic link, the difference is that it copies the original and creates a copy; when the original is deleted, the symbolic link becomes unusable, but a hard link can still be used because it is the same file after all; links that are involved in the number of links.

Code

ln [대상 폴더] [만들 링크 파일명] # Hard Link
ln -s [대상 폴더] [만들 링크 파일명] # Symbolic Link

The erase command can be lifted with rm, just like erasing a file

Diff & Patch

diff a b > difference.patch

The diff command compares two files on a line-by-line basis, and the patch command allows you to modify a file based on the comparison made by diff.

patch -p{패치 경로의 depth} [원본] [patch 파일] # 패치 파일 적용
patch -p{패치 경로의 depth} -R [원본] [patch 파일] # 적용된 패치 파일을 되돌림

In the same form as above, you can apply and remove the contents determined through diff from an existing file.