Shell

The difference between one, ' and $ ()The anti-quote itself escapes the \, retains its own meaning, and if we want to play a special meaning in the anti-quote, we must use 2 \ to represent it. in inverted quotation marks: \ \ = \$ () in: \ = \Note:

The difference between 1, ' and $ ()The anti-quote itself escapes the \, retains its own meaning, and if we want to play a special meaning in the anti-quote, we have to use 2 \ to represent it. So we can simply imagine the inverted quote: \ \ = \$ ()

Reference article: http://blog.csdn.net/chen_jp/article/details/8922582One-character substitutionOrigin= the original string str= the replaced stringReplace command:str=${origin//the target character / replaced character }For example:str=${origin//:/

1.Tenth LineHow would you print just the 10th line of a file?For example, assume this file.txt has the following content:Line 1Line 2Line 3Line 4Line 5Line 6Line 7Line 8Line 9Line 10Your script should output the tenth line, which is:Line 10----------

SED commandUseProvides the flow editor.Grammarsed [-n] Script [File ...]sed [-n] [-e Script] ... [-F ScriptFile] ... [File ...]DescribeThe SED command modifies the row from the specified File parameter according to the edit script and writes the

The basic meaning of shell variable $#,[email protected],$0,$1,$2 in Linux:Variable 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

For i in ' cat T1 '; Do echo "$i" | awk ' {sub (/^ */, ""); Sub (/*$/, "")}1 ' >> tem1; DoneFor i in ' Cat T2 '; Do echo "$i" | awk ' {sub (/^ */, ""); Sub (/*$/, "")}1 ' >> tem2; DoneCat Tem1 >> TEM3Cat tem2 >> TEM3Cat Tem3|sort|uniq-c |awk ' {if ($

Bash variables: User-defined variables, environment variables, positional parameter variables, predefined variablesUser-defined variables:#变量赋值等号两侧不能有空格#调用变量加 $ eg. Echo $x#变量的叠加: x= "$x" 456 or x=${x}789Set #查看变量Set-u #echo时看变量是否存在unset variable

1. Create an alias$ alias dms='cd oracle/middleware/user_projects/domains/7001_costctl/'pwd /home/weblogic/oracle/middleware/user_projects/domains/7001_costctlCreating an alias is only temporary, and once the alias for the terminal setting is turned

Test instructionsGive a continuous coloring method of 1-n beads A[i] (1Analysis:The DP equation can be obtained: Dp[n] =∑ (i=1,n) (Dp[n-i]*a[i]).The equation is convolution form, so CDQ + FFT　　CDQ: Will [L,r] two points, first get [L,mid] answer,

Sort commandSort is output in ascending order of ASCII code, and is compared sequentially from the first characterCommon options-C test file is already sorted-R Reverse Sort-N Sort by numeric numeric size-t Specifies the separator-K Specify Domain-U

Cut command common optionsThe test text content is as follows:# cat Name1.txt name1 alvin1name2 alvin2name3 alvin3name4 alvin4# cat 2.txt name1:100name2:101name3:102(1)-CCut the 1th character of each column# Cat Name1.txt | Cut-c1NNNNCut the 1th, 3-4

Performance testing, you may change the environment to change, each time the test, the configuration file is different, may cause the test to fail.Suppose there is a correct configuration file for Zoo.cfg.template, and the configuration file for the

Test text content# cat-n Name1.txt 1name1 alvin1 2name2 alvin2 3name3 alvin3 4name4 alvin4# cat-n name2.txt 1name1 1 XX 2name2 101 3name3 102 4CCCCCCCCCCCCCCCC(1) JoinDisplay matching rows and merge values (CCC and

In the shell, arguments can be passed to a function when it is called. Inside the function body, the value of the parameter is obtained in the form of a $n, for example, "$" for the first argument, and $ for the second

Tag: exec source ForkFork is a system call to Linux that creates a child process that is a copy of the parent process, obtains a certain resource allocation from the parent process, and inherits the environment of the parent process. The only

First, several commands are elaborated.Echo $ shows the currently used shell versionDpkg-reconfigure Setting the package typeThe reason why the newspaper is wrong:The default shell parsing used by Ubuntu is a feature that Dash,dash only part of

Before I wanted to print out the code, it seemed that, after merging, I found that there were more than 2000 pages in Word and then dropped the ~anyway, which was very useful.For example I have text A001.dat, A002.dat, A003.dat ... and then want to

First, define variablesDefine variable names without a $ (unlike PHP, as with Python), with no spaces between variable names and "=" (special, unlike other languages)Example: x= "Hello World"Note: The naming of variable names should follow the

Shell Array(1) Defining an arrayIn the shell, the array is represented by parentheses, and the array elements are separated by spaces, defining the general form of the arrayArrt_name=(val1 val2 val3) or arry_name=(VAL1VAR2VAL3VAL4) or