Shell

Thank you for the 36,000 sectionCommon Shell Categories: BASH: is the GNU Bourne Again Shell, which is the default shell on the GNU operating system C Shell: The BSD version of Sun's shell Look at where the shell is on the

#字符串: As the number is the most commonly used type, the other is nothing to use.#字符串可以使用单引号, double quotes, without quotes.#单引号字符串限制:# 1. Any character is output as is, and the variable in single quotation marks is invalid# 2. Single quotes cannot

*-----Wildcard (multi-bit)?-----wildcard character (one bit)#-----Comment (Explanatory Note)\-----caret (\ #1. txt, let #1.txt become a file name, so that the special symbol behind the loss of meaning)|-----Give the result of one command to another

I. Shell BasicsCat/etc/shells the shell that the current operating system can useWhat is a shell?A text file that implements a function that has permission to executeCommand-line InterpreterBuilt-in commands (commands provided internally by the

#!/bin/bashSource/etc/profileSOURCE ~/.bash_profile##################################00 * * */bin/bash/utxt/soft/tools/rm_oracle.sh >>/utxt/soft/tools/rm_oracle.log 2>&1#################################lyd_rm_dt= ' date-d '-5 day "+%y%m%d"flow_rm_dt=

1.shell Introduction The shell is a special-function program that provides an interface for users to interact with the kernel. It is used to receive commands entered by the user and send it to the kernel for execution. The shell is an

Use directly after declaring variables in the shell:#！ /bin/bashNa=zhagnsanag=11Echo ' $na is $ag years old 'Output: $na is $ag years oldecho "$na is $ag years-old"Output: Zhagnsan is one years oldTherefore, use "" in shell scripts to output

#!/bin/bash# the is script backup /etc directory! # author: zhangjun  (e-maill: [email protected]) date=$ (date +%y%m%d) size=$ (du -SH/ETC) if [ -d /tmp/dbbak ]         then                echo  "date:  $date!"  > /tmp/dbbak/dbinfo.txt              

LinuxLinux CSHRC file functionsHow Linux processes/view process/kill processWhat permissions does Linux file 755 represent?Linux worker threadsLinux inter-Process communication methodPipeline,msgq ...Inter-process Communication _ Baidu

Shell parameter substitution xargs. Parameters that generate the command1. Cut-d ': '-f 1/etc/passwd | Head-n 3 | Xargs finger　　2. Ask the user before executingCut-d ': '-f 1/etc/passwd | Head-n 3 | Xargs-p FingerIf you press ENTER directly, exit　　3.

1. Numerical test Parameters Description -eq Equals is True -gt is greater than true -lt is less than true -nq Not equal to True -ge

Day01Write a script to do the following: Enter a number, and then run the corresponding command. The display command is as follows: *cmd meau** 1---date 2--ls 3--who 4--pwdWhen you enter 1 o'clock, you run the date, enter 2 o'clock to run LS, and so

1. Condition Judgment:If use:if condition; Then commands; fiIf else uses:if condition; Then commands; Else if Then commands; Else commands; fiDescription&&| | action; # If condition is false, the action is executed. && is the logic and operator, |

1. Shell Tutorial1. Shell TutorialThe shell is a program written in C and a bridge for users to use Linux. Linux is both a command language and a programming language. A shell is an application that provides an interface through which users access

Toggle command line: CTRL+ALT+F1-F6 Switch to graphical interface: CTRL+ALT+F7 Ls-list (dir under Win)White: Normal fileBlue: Catalog FileGreen: Executable fileTo perform the steps: Input ls In the relevant directory go to the

Commonly used arithmetic operators, assuming that variable A is 10 and variable B is 20:Operator Description Example+ addition ' expr $a + $b ' result is 30.- subtraction ' expr $a-$b ' result is 10.* multiply ' expr $a \* $b ' result is 200.

Types of variables:1. Custom variablesDefine variables: Variable name = variable value variable name must start with a letter or underscore, case sensitive url1=test.3glong.comReference variable: $ variable name or ${variable name}View variables:

# netstat-an| grep ': 80 ' | awk '/tcp/{a[$NF]++}end{for (i in a) print i,a[i]} '# echo "Current concurrency: ' netstat-ant | grep:80 | awk ' {print $} ' | Awk-f ":" ' {print $} ' | Sort | uniq-c | Sort-r-N | awk ' begin{total=0}{total+=$1}end{print

One, the file operation1. Expression-D: Whether it is a directory-F: Whether it is a file-E: Whether the file or directory exists-R: Whether the current user has Read permissions-W: Whether the current user writes permissions-X: Whether the current

Python is a very easy way to solve repetitive strings, such as a= "James", so to get "Jamesjamesjames" is "a*3".But this "*" string multiplication in the shell is not, for example, "to output 10 a", do not want to use for the loop to do, how to