Shell

Shell IntroductionThe shell is the interface between the user and the Linux operating system. There are multiple shells in Linux, where bash is used by default. The shell of the Linux system, as the shell of the operating system, provides the user

Array Assignment: A= (1 2 3 4 5)A[1]=1 Array length: Echo ${#a [@]} or echo ${#a [*]} Read array: Echo ${a[@]} or Echo ${a[*]}echo ${a[0]} PS: array subscript starting from 0Delete array: unset aUnset A[1]Array fragmentation: Echo ${a[@]:0:3}

Shell-Used regular expressions "^\d+$"//non-negative Integer (positive integer + 0)"^[0-9]*[1-9][0-9]*$"//Positive integer"^ ((-\d+) | (0+)) $ "//non-positive integer (negative integer + 0)"^-[0-9]*[1-9][0-9]*$"//Negative integer"^-?\d+$"//Integer"^

1. Install Mutt mail Client # yum Install Mutt-y 2. Create a script # vi/etc/rc.d/mail_to_bak_daily.sh Version One: #!/bin/bash # ========================================================= # Please enter which

Here are 5 interview questions to continue the previous questions and answers about Linux interviews. If you are a tecmint reader, I am very grateful for your support. 1. Write a shell script to get the current date, time, username and current

A. Shell Game time limit/test 0.5 seconds memory limit per test 256 megabytes input standard input output standard out Put Bomboslav likes to look out of the ' window in ' his room and watch lads outside playing shell famous. The game is played by

First, the comparison table: The test results for the sequencing program mentioned in section I of chapter I are as follows:┌──────┬─────────┬────────┐│ Project │c│ combination language │├──────┼─────────┼────────┤│ source program length │1,363

If condition test common syntax Test [] [[]] ()) Test command AND [] testing operator Test [] (these two syntaxes are equivalent) test operator full Spell

20.10 for Loop Syntax: for variable name in condition; Do ...; Done ;案例1[[email protected] shell]# cat for.sh#!/bin/bashsum=0for i in `seq 1 100`do sum=$[$sum+$i]doneecho $sum#输出的结果[[email protected] shell]# sh for.sh 5050

[[email protected] ~]# ls111 234 anaconda-ks.cfg Dir3 test5 Yum.log123 2.txt a.txt dir4 Testb.txt Learning Schedule1_hard.txt 2.txt.bak BB split_dir testc.txt1.txt 3.txt dir2 test4 Thinking_in_java (Chinese Version _ Fourth edition). pdf[[email

Bash should be the most important thing we have in daily work, like our most loyal friends, and we need to know the "habits" of this friend.Bash has several different modes of operation, the login shell and the Non-login shell,interactive shell and

A. Regular Expressions:Metacharacters is a character used to illustrate the meaning of a character expression, in short, a character used to describe a character.The regular expression re (Regular expression) is a string of characters consisting of

Enter HBase Shell Console$HBASE _home/bin/hbase ShellIf you have Kerberos authentication, you need to use the appropriate keytab for authentication (using the Kinit command), and then use the HBase shell to enter the certificate successfully. You

Excerpt from: Abs_guide: http://www.tldp.org/LDP/abs/abs-guide.pdf the meaning of shell variable $#,[email protected],$0,$1,$2 in Linux is explained:Variable Description:$$ the PID of the shell itself (ProcessID)$! PID of the Shell's

background: In the remote file download, you need to enter the other party's server password, the shell does not support interactive input content, can be implemented in the following two ways I. Embedding expect in shell scripts for password

In the loop, sometimes you need to force out of the loop when the loop end condition is not reached, like most programming languages, the shell also uses break and continue to jump out of the loop.Break commandThe break command allows you to jump

The 25th chapter in-depth discussion When the shell sees Cat >> Tmpfile This was the first line> this is the second line> third> Forth>.....>do CWhere Doc is the delimiter, when you enter Doc again in a new line, it means that the input is complete.

In the history of migrating innovative products from Silicon Valley, Quora, a social networking site, is a relatively special object to be examined-it is far away from business, it is also squeezed out by search engines and social networks. As a

Bourne shell Introduction: Bourne shell basics and many other useful features, shell programming and organization. Main content:Basic Introduction to. Shell, environment, options, and special characters. Shell variables User-Defined variables,

5.2 Bash Variables The following variables are set or used in Bash. Other shells generally do not process these variables. Some variables used by Bash are also described in other chapters: for example, for variables used by tools for controlling