Shell

Typical examples:A=dateEcho $a establishedA =dateecho $a not set upActually, the reason is simple.The principle of the shell in interpreting the command is that the first symbol tag can only be a program or a command, when there is a space, the

One, single and double quotation marksFirst, both single and double quotes are meant to solve the problem of having spaces in the middle.The space is used as a typical delimiter in Linux, such as String1=this is a string, so execution will be an

(i) SEDSed is a streamlined, non-interactive, streaming editor that enters edit commands and specifies file names on the command line, and then looks at the output on the screen.The content of a progressive read file is stored in a temporary buffer

Meet Meaning && Command1 && command2: Command 1 returns True (command return value $? = = 0) after which command 2 talent is run. Can be used for if inference.CP 1.txt.. /&& echo "succes" #-->successCP 1.txt.. /&& rm-f.

Diff diir_1.0/dir_2.0/-urnb > dir_2.0.patchU:union output file differential information in a merged formatR: Recursive comparison of all files in subdirectoriesU: Treats non-existent files as empty filesB: Ignore the differences caused by empty rows~

First, bash1.bash is also a program, when is the program called?User login, using the SU command to switch users, directly execute the BASH command will open a new bash, this shell called the child shell, the child shell can not be the same as the

Transferred from: http://www.cnblogs.com/sunyubo/archive/2011/10/17/2282047.html1. Shell to determine the file, whether the directory exists or has permissions2. #!/bin/sh3.4. Mypath= "/var/log/httpd/"5. myfile= "/var/log/httpd/access.log"6.7. # the-

shell scripting Introduction and common Tools Shell Script Shell script: is actually a batch script in Windows, multiple shell command collections that can be executed at once. Scripts on Linux can be implemented in a number of

The line end flags for Linux and Windows text files are different. In Linux, the text file uses "/n" for carriage return, while Windows uses "/r/n" to indicate carriage return line breaks. Sometimes you need to be aware of this when writing shell

#!/bin/bash#by lc ip= ' ifconfig eth0|awk -f  ' [ :]+ '   ' NR==2{print $4} ' zhandian=/data01/static/shareextra=haixiang.conftoolsdir=/application/toolsnginxdir=/application/

Environment settings for the terminal of the Bash shell usage environment: stty Environment settings for the terminal of the Bash shell usage environment: stty STTY-A Lists all the current stty parameters to INTR: Sending an interrupt

Shell scripting, there are three kinds of control structure are: sequential structure, conditional judgment structure, loop structure. This article summarizes the use of conditional judgment constructs in shell scripts.The structure of conditional

1.shell OverviewThe shell is a command-line interpreter that provides the user with an interface system-level program that sends a request to the Linux kernel to run the program, and the user can start with the shell, suspend, stop, or even write

Get the date of the dayDate +%y-%m-%dOutput: 2011-07-28Assigns the current date to a date variabledate=$ (Date +%y%m%d)Sometimes we need to use dates before or after today, so we can use the-D parameter of dateGet Tomorrow's dateDate-d Next-day

$ () and ' (anti-quote)In the bash shell, $ () and "(anti-quote) are used for command substitution.The so-called command substitution is similar to the variable substitution we learned in the fifth chapter, which is used to reorganize the command

Today I suddenly wondered how many lines of code I had written recently, and then I used the shell to figure out the most recent code: ? 1 Find/home/chengshuguang/mango-maxdepth 1-name ' *.c '-or-name ' *.cpp '-or-name ' *.h ' |

1. Core-Responsible key functionssystem memory management, software program management, hardware Device management, file system management2.GNU tool ChainThe Linux kernel is the core of the system, controlling how memory, programs, and hardware

Special usage of $0,$?,$! in shellVariable Description:$$The PID of the shell itself (ProcessID)$!PID of the Shell's last running background process$?End code of the last Run command (return value)$-Flag at a glance using the SET command$*All

A, delete all data tables for the specified database#!/bin/bash# Delete all tables in MySQL # example: # Usage:./Script user Password dbnane# Usage:./script User Password Dbnane server-ip# Usage:./script user Password Dbnane mysql.nixcraft.inch# ----

Command editing ability (history):One of the great features of Bash is that "he can remember the commands he used!" "This is a really great feature!" Because I just press "up and down" in the command column to find the front/rear input command! In