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Linux/Unix
Linux is a clone of Unix operating system, it is a multi-user operating system, which can be accessed by many users at a time.
Linux Server Management
Linux server management service is a cost-effective mixture for the application-based server. Essential applications deployed on Linux servers need the right management solutions or tools. Large enterprises and end-users require robust Linux servers to manage applications for their business.
In this tutorial, you will learn the very basic Linux commands that will help you to get more familiar with the Linux command line. This will also help you to sharpen the commands line in Linux as well as also help you in enhancing your capability of getting an expert in this field.
Commands
The commands in Linux have the following syntax:
$command options arguments
Bash/shell: Program that provides text-only interface.
Terminal: A terminal window
Command-line : Anything that takes input
Console: Physical instrument panel
1) $ls : Used to show the folders & web files
2) $ls -a : List all the files and folders.
3) $ls -l :Used to list folders with permissions
4) $ls Do* : Listing all the folders starting with Do also print inside files
5) $ls .* : Listing all the files starting with (.)
6) $ls -a : listing all the folders and files, including hidden files
7) $cd : To jump in the folder
8) $cd .. : To go back to the folder.
9) $cd ../.. : To jump back to the two directories.
10) $mkdir : To make the directory/folder
11) $mkdir -p : To make the directory/folder one to one inside in it.
Example:
12) $mkdir -vp : to make the directory and it will print the dir. created.
Example-
13) $touch pop : to make the new file(pop) in folder
14) $touch grapes oranges : to make a recursive file(grapes,oranges) in a folder.
15) $mv : to move the file from source to destination.
16) $cp : to copy a file from one folder to another.
17) $rm : Delete the file or folder
18) $rm -r file name/ : Remove the folder
19) $rm -r a b c : remove the files from the folder
20) $whereis (command name) : To find the actual path of the command.
21) $echo -e “paul \nlikes \necho”
-
It will print each char in next line
22) $ x=paul
23) $ echo “ $x \nlikes \necho”
-
It will also print the x value
Find command
Find command is used to search and locate the list of files and directories based on conditions you specify for files that match the arguments. Find can be used in a variety of conditions like you can find files by permissions, users, groups, file type, date, size, and other possible criteria
Note: (.) is for the current directory
24.) $ find . -name file_name / dir._name
Used to find the file/directory in the current directory
25.) $ find . -type f/d -empty
To find the empty dir/ file ** f for file & d for directory
26) $ find . -mtime -1
To find the file/directory which is made within one day
27) $ find . -mtime +1
To find the file/dir. which was made 1 day ago
28) $find . -mmin 1
To find the file/dir. which was made 1 min ago/ To find the file/dir which is made within 1 min.
29) $ find ./ type d/f -name file/dir
To find the directory / file
** f for file and d for directory
30) $ find . *.extension
To find the all file which is with the assigned extension.
** here there is no .jpg file available
31) $ find dir.name
To show all the files and directories
32) $ find -iname “char*”
To find all the files and dir. starting with the f* and -i not including case sensitivity
33) $ find ./ -type f/d -iname “f*”
To find file or directory with disable case sensitivity and listing files / dir with f*
34) $ find . -size +0
This will show the file presented in the current directory which is more than 0 mega byte.
** G = GB
** K= KB
35) $ du -sh file/dir
It will give the size of the file or directory in KB
Vi editor
After $ vi d1 write the text by pressing (I for Insert )click→ Esc→ shift + :→ wq → Enter
GREP – Global Regular Expression Print
“It allow us to search text within files in a system”
36) $ grep [binary digit] file_name
It will search the binary number which are inserted in the square bracket.
37) $ grep -w “string” file_name
It will only show the valid text inserted in the inverted commas.
38) $ grep -i “string” file_name
It is non-case sensitive command ( -i )
39) $ grep “string” file_name
Show all the matching text.
40) $grep -win “string” file_name
Show at which line the text resides.
41) $ grep -win -B 4 “string” file_name
Show the 4 line before the inserted text.
Show the 2 lines above and below the text.
Show the 2 lines after the text
42) $ grep -win -A2 ‘String” d1
43) $ grep -winr “string” ./*
[centos@localhost ~]$ grep -winr “cat” ./*
It will show all the files and folders with the string.
AWK command (Aho, Weinberger and Kernighan)
It is just a scripting language used to it doesn’t require compilation time and it generates reports by processing file. It is beneficial for pattern searching and processing files.
Various programming concepts offered by AWK are:
1) Output formatting
2) Inbuilt variables
3) Pattern matching
4) String operations
5) Arithmetic operations
Basic syntax
# awk options ‘selection _criteria {action }’ input-file > output-file
Awk assign some variables for each field.
→ $0 denotes the whole file
→ $1 denotes the first field
→ $2 denotes the second field
And $3,$4,$5…..so on for every field.
Commands related AWK
44) # awk ‘{print $variable}’ file_name
This command will print the field according to the variable
45) # awk –version
We can also check the version of the awk.
# awk -F: ‘{print $variable}’ filename
This will print the file without the separator (i.e. [:])
46) # echo “string” | awk ‘{$variable=”string”; print $variable}’
This will replace the string manish to raghav and print the whole string.
47) # cat file_name | awk ‘{$variable=”string”; print $variable}’
This command will replace the particular string which is in field 2 and print the whole file content.
48) # awk ‘/string/’ file_name
This command will show each line that contains the following word i.e.( or )
49) # awk ‘$variable==”char” {print $variable}’ file_name
T
his will print 5th field if the field 1 value matches the value 300 in the file.
CUT command
The cut command basically a Unix command line utility which extracts section from each line.
Basically the cut command slices a line and extracts the text.
50) # cat -b variable file_name
This cut command will extract the following byte (-b) from the file.
51) # cut -d ‘delimiter’ -f field/ranges/sequence file_name
This command will show the following fields/ranges from the file
if -d option is not used then it prints whole line:
52) # cut -c variable file_name
This command will print each character from the file starting from 1st field.
53) # cut –complement -d “ “ -f variable file_name
This command will print each field except the 3rd field
54) # echo field >> file_name
This command will permanently add on the field at last into the file
55) # cut -d “ “ -fvariable file_name
This command will show only the 3rd field from the file
SED command
It is also called stream editor, it is a powerful linux/unix utility tool used for text manipulation, finding, deletion, saving permanently, etc.
s: means substitute
g: means globally
56) # sed ‘s/string1/string2/g’ file_name
This command will change the string1 to string2
57) # sed /\bstring1\b/string2/g’ file_name
This will replace the exact matching word list into raghav in the file.
58) # sed ‘s/^string1/string2/g’ file_name
This command will change the value which ends with $ sign in the file.
Deletion
59) # sed ‘/word/d’ file_name
This command will delete the particular line which consists of the particular word.
‘d’ denotes the delete.
Saving permanently to the file
60) # sed -i ‘s/char1/char2/g’ file_name
-i → use this -i ,if you want to change or modify directly to the file
This -i can be used at the above sed commands this will permanently save every modification in the file.
Conclusion: By following this tutorial you will get the basic understanding of Linux commands