常用命令

脚本里会用到的，非外部工具，尽量举例说明

TODO

#Creates a physical link.
ln file1 file2

#Creates a symbolic link.
- ln -s source_file target

xxd #查看二进制
objdump #查看二进制
file #查看文件信息
ps -e

du

Show disk usage.

locate

It is used to locate a file in Linux System

df

It is used to see the available disk space in each of the partitions in your system.

tar

Used to work with tarballs (or files compressed in a tarball archive)

mv

Used to move the files or directories. This command’s working is almost similar to cp command but it deletes a copy of the file or directory from the source path. - Move multiple files

mv a.py b.py c.py Dir
mv a b c -t Dir

chown

Used to change the owner of the file.

chgrp

Used to change the group owner of the file.

chmod

Used to modify the access/permission of a user.

#+ : add a permission
#- : cancel a permission
#=: add some permissions and can other permissions(if has)
#r: read x:Executable w: write
chmod +w file.sh
# 所有者读写权限（6），所属组有读权限（4），其他用户没有权限（0）
sudo chmod 640 .sshkey/id_rsa

more

It is a filter for paging through text one screenful at a time.

less

It is used to viewing the files instead of opening the file.Similar to more command but it allows backward as well as forward movement.

head

Used to print the first N lines of a file. It accepts N as input and the default value of N is 10.

tail

Used to print the last N-1 lines of a file. It accepts N as input and the default value of N is 10.

grep

This command is used to search for the specified text in a file.

sort

This command is used to sort the contents of files.

wc

Used to count the number of characters, words in a file.

cut

Used to cut a specified part of a file.

awk

command line数据处理

sed

截取文件内容，格式匹配