The Linux/shell of the interview question summary

Linux

Linux CSHRC file functions

How Linux processes/view process/kill process

What permissions does Linux file 755 represent?

Linux worker threads

Linux inter-Process communication method

Pipeline,msgq ...

Inter-process Communication _ Baidu Encyclopedia

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Shell

What is $*?
Would display all the commandline arguments that is passed to the script

What's the difference between a shell variable that's exported and the one that's not exported?
Export Lang=c
Would make the variable LANG the global variable and put it into the global environment. All and processes can use it.
Lang=c
Would change the value of the current script.

How would you list only the empty lines in a file (using grep)?
grep "^[]*$" filename.txt
In character set (between [and] one space and tab is given)
This command would gives all the blank line including those have space and tabs (if pressed) only

How does the read arguments in a shell program-$ $?
#!/bin/sh
For I in $*
Do
Echo $i
Done
On Executig the above script with any number of command-line arguments it would display all the Parametsrs.

How would do I get the character positions 10-20 from a text file?
Cut-c10-20 <filename.txt>
Or
Cat Filename.txt | Cut-c 10-20

The Linux/shell of the interview question summary