learning bash shell

From: http://share.blog.51cto.com/278008/583382 I wrote a very simple script to upload a file to a directory of HDFS in hadoop. When you enter the file name or directory name, an error occurs sometimes and you need to delete the incorrect input. However, when you press the backspace key, garbled characters (^ h) are displayed. Each time you press the backspace key, a ^ h occurs.Search for online materials and refer to the following webpage to find a solution:First, press and hold the ctrl k

Come t00ls a few days, also have no time to write original. --(I started the toast.) ）Recently saw a foreigner an article, feel very good.Test a bit of this thing to share the process to the guys, hope that everyone do not step on, busy these days to write originalCall a JS, scan the intranet for bash vulnerabilities, and then bounce back a small thing from the shell. Apt should be used.Test process:A POC f

File systemDescribes the mount command that did not correctly enter the third step above.Tips:1. BusyBox has ash and hush and sh these shells, in the command line input ash or hush, you can like in bash, by pressing the up and down keys to select the command just entered.2. The Android system itself has the LS command, BusyBox also has LS, the input LS is called the Android LS, then want to use BusyBox ls to each time in the front add a busybox? No,

Resolve Bash Shell pin this newspaper error ': not a valid identifierWhen you edit the script in the shell, the runtime appears "': not a valid identifier", or it will appear (: Command not found, many inexplicable symbols) is likely you to edit under Windows, run under Linux, Due to different text formats for Linux and Windows.The above may be one of the reactio

A basic Bash shell command (based on Ubuntu implementation) The/etc/passwd file contains a list of all system user accounts and basic configuration information for each user. Man commandEnter the man command before the name of the tool you want to find, and you'll find the manual entry for that tool. Space PAGE Down Carriage return downward line-wise b PAGE Up Q exit Linux top-leve

Set font and background color under BASH shell\e[30m change the display color of a character to black\e[31m change the display color of a character to red\e[32m change the display color of a character to green\e[33m change the display color of a character to light red\e[34m change the display color of a character to blue\e[35m change the display color of a character to purple\e[36m change the display color

Bash Shell usage notesThe use of the shell is profound, I comb the basic knowledge, tidy up a simple usage, the specific requirements for self-study.1. calculation #echo$ ((1+2)) 3#echo$ ((1+2+3)) 6#echo3+2+5|bc102. If usage if[ $i -eq0];thenxxxelse xxxfi integers compare:-eq equals, such as:if[ "$a" -eq "$b" ]-ne not equal, such as: if [ "$a" -ne "$b" ]-gt great

In Linux, shell is a commonly used tool. In Red Hat Linux, we usually use B shell or bash. In Shell, we always want to set some environment variables or other initialization operations when opening this shell. But how can we do this? Although we can use the set or Export Sta

$ echo the last argument is$$#The last argument is $4$ eval echo the last argument is$$#The last argument is D[Email protected]:~$ set-x//Open bash shell debug function[Email protected]:~$ eval echo the last argument is $$#+ eval echo the last argument is ' $4 '+ + echo the last argument is DThe last argument is DIv. Exit commandThe exit command ends the script to return to the command line.The exit command

1 exec BuiltinDo not create a child shell, start a new script on the original process, but it will clean up the environment of the old shell, so it does not inherit from the original shell, execute the new script in a clean environment. Exit the current shell after execution is complete.2 Source BuiltinDo not create a

, and if a floating-point number is required, it needs to be done in BC.As for the brackets [], the sensory function is used to compare. For example, in the IF statement inside, while statement inside, and so on.This leads to the [..] and [[...]] The difference: (from an online, measured confirmation): use [[...]] The conditional judgment structure, rather than [...], prevents many logic errors in the script. For example, , | |, The difference between single quotes, double quotes, and anti-quote

repair success.Patching ScenariosCentos:Yum clean allyum makecacheyum-y Update bashUbuntu:Apt-cache gencachesapt-get-y Install--only-upgrade bashDebian 7.5 64bit 32bit:Apt-cache gencachesapt-get-y Install--only-upgrade bashDebian 6.0.x 64bitwget http://mirrors.aliyun.com/debian/pool/main/b/bash/bash_4.1-3+deb6u2_amd64.deb dpkg-i bash_ 4.1-3+deb6u2_amd64.debDebian 6.0.x 32bitwget http://mirrors.aliyun.com/debian/pool/main/b/

Tags: operations shell scripting frequent access to the Internet part of the mutual summaryIn daily work, the bash shell has a very frequent time operation. For example, when the shell script sends statistics periodically, it will check whether the scheduled send time is current. Or when you use a file to save some dat

displayed afterUse of the echo command-E\b: Delete the preceding character\ t; tab\v: Vertical tab\ n: Line break\onnnStart \033[# ## 1-7 Front View# # Background ColorEnd \033[0m-N: Do not wrap text for displayFile operationsCP src DestIf SRC is a fileIf the target is a file and the target exists, overwriteIf the destination file does not exist, create a new fileIf the target exists and is a directory, copy the source to the destination directory and keep the originalIf SRC has multiple filesI

Save a script file under Windows, upload to CentOS with SSH, add permission to execute Nginx prompt without that file or directory.The shell script is placed in the/etc/init.d/directory, and then executes the/etc/init.d/nginx, prompting more of this sentence/bin/bash^m:bad interpreter.We found the information on the Internet.If the script is edited under Windows, it is possible to convert it to a DOS text f

One of the basic features of the bash shellFirst, the Order historyBash records the command that the user executed in the shell session in the buffer, and when it exits normally, it is recorded in the current user's home directory. Bash_history;Environment variables:Histsize: The number of records in the command history;Histfile: Command history file path;Histfilesize:History command:-C: Clears the command

Determine if the contents of a file are not empty, use the statement: If test-z ' cat filename ' When the filename is empty or there is only one line of strings without spaces, all normal, on the contrary, will report: Too many arguments, or even: binary operator and other errors. Reference article: http://www.ibm.com/developerworks/cn/linux/shell/bash/bash-2/

Article title: shell introduction-bash programming-process control (2 ). Linux is a technology channel of the IT lab in China. Includes basic categories such as desktop applications, Linux system management, kernel research, embedded systems, and open source. F :: While Syntax: While (condition) Do Commands Done For example: #! /Bin/bash Number = 0 While (test $

~/tscripts $ unset namereadonly6. Non-read-only variable can be canceled, cancel print to empty[Email protected] ~/tscripts $ unname=~/~/tscripts $ echo $unname7. Single quotation marks~ $ name='Leo'$name ' $'name'8. Double quotes" I am $name " "\\i am $name \ \"\i am Leo \9. Stitching strings" He is $name " is "$name is handsome"! is handsome! "$name is handsome! "-bash:! " : Event not found10. Get the string length[Email protected] ~ $ echo ${

inserted at the current position, for example, a CTRL-V can insert a character at the current position, where ASCII is 9, otherwise the result is usually followed by a command The CTRL-C removes the edit of the current command line from another line. The CTRL-S temporarily freezes the input of the Current Shell CTRL-Q unfreeze ESC-C: make the first letter of the next word in uppercase, and move the cursor forward to a word. For example, if the cursor