Linux Reading Notes

Type \

Echo unset set Export

Environment variable: Home shell histsize mail path Lang random PS1 $?

Language variable that affects the result: locale

Variable keyboard reading, array and Declaration: Read array declare

And file systems andProgramConstraints: ulimit

Deletion, substitution, and replacement of variable content:

Delete

$ {Variable # keyword} Only deletes the shortest prefix-> suffix

$ {Variable ## keyword} Only deletes the longest prefix-> suffix

$ {Variable % keyword} After Shortest-> before

$ {Variable % keyword} longest last-> front

Replace

Replace $ {Variable/old string/new string} with the first variable

$ {Variable/old string/new string} replace all

Variable test and content replacement

Bash logon and welcome information

/Etc/issue/etc/motd

Bash environment configuration file

/Etc/profile

~ /. Bash_profile ~ /. Bash_login ~ /. Profile

Read environment configuration file

Source.

Terminal Environment Settings

Stty set

Data Stream redirection

Stdin: 0 stdout: 1 stderr: 2

/Dev/null

2> & 1

Eg: CAT> catfile <"EOF" When EOF is input, end the input, instead of ^ d.

Command Execution judgment basis

;

& | $?

MPs queue

Select command:

Cut-d' delimiter '-F fields cut-C character range

Eg: Echo $ PATH | cut-d': '-F 1, 3; echo $ path cut-C 12 -;

Grep [-acinv] [-- color = auto] 'query string' filename

Sort command:

Sort [-fbmnrtuk]

Uniq [-ic]

WC [-LWM]