Strength for Engineering Students

1. Log into the system
2. Use ‘VI” editor to create a file called myfile.txt which contains some text.
3. Correct typing errors  during creation
4. Save the file
5. Logout of the system

Log into the system

When we return on the system one screen will appear. In this we have to type 100.0.0.9 then we enter into editor. It asks our details such as          Login : krishnasai          password: Then we get log into the commands.

Use vi editor to create a file called myfile.txt which contains some text

Syntax:-vi file name Description:  Ø  Vi Command is used to create and editing a file; Ø  If we type "vi filename". ü  If the file named filename exists, then the first page (or screen) of the file will be                  displayed; ü  If the file does not exist, then an empty file and screen are created into which you may enter text. Example: vi myfile.text.

Correct typing errors  during creation

In creating a file through vi editor an error an error will occur we  modify the file by  opening the file again. An error will occur when we don’t give space between filename and command name Example: vikrishnasai

Save the File.

To save the file created in vi editor we press esc “:WQ” .It means that saves the file and  Quits editing mode .then we come out from the vi editor. :wq:- quit vi, writing out modified file to file named in original invocation :q!:- quit vi even though latest changes have not been saved for this vi call :x:- quit vi, writing out modified file to file named in original invocation

Logout the system.

Syntax: exit Description: In our current directory press exit to log out from the commands

1. Log into the system
2. Open the file created in session-1.
3. Add some text
4. Change some text
5. Delete some text.
6. Save the file
7. Logout of the system

a.      Log into the system

When we return on the system one screen will appear. In this we have to type 100.0.0.9 then we enter into editor. It asks our details such as          Login : krishnasai          password: Then we get log into the commands.

b.      Open the file created in session -1

Syntax: vi filename In the above session we create a file in vi editor To open the  file created in  Session 1 we have to type as follows  “vi filename”

c.       Add Some text:

To add some text to the file which is already created first we have to open that file then add text. vi filename. Text The following commands allow you to insert and add text. Each of these commands puts the vi editor into insert mode; thus, the <Esc> key must be pressed to terminate the entry of text and to put the vi editor back into command mode. Ø  i:- insert text before cursor, until <Esc> hit Ø  I:- insert text at beginning of current line, until <Esc> hit Ø  a:- append text after cursor, until <Esc> hit Ø  A:- append text to end of current line, until <Esc> hit Ø  o:- open and put text in a new line below current line, until <Esc> hit Ø  O:- open and put text in a new line above current line, until <Esc> hit

d.      Changing Text

To change the some text in myfile. text move the cursor where we want to change the text After that replace the text under cursor with other text first open the file as follows. vi myfile.text The following commands allow you to modify text. Ø  r:- replace single character under cursor (no <Esc> needed) Ø  R:- replace characters, starting with current cursor position, until <Esc> hit Ø  cw:- change the current word with new text, starting with the character under cursor, until <Esc> hit Ø  cNw:-change N words beginning with character under cursor, until <Esc> hit; Ø  e.g., c5w changes 5 words Ø  C:- change (replace) the characters in the current line, until <Esc> hit Ø  cc:- change (replace) the entire current line, stopping when <Esc> is hit Ø  Ncc or cNc:-change (replace) the next N lines, starting with the current line, stopping when <Esc> is hit

e.       Delete some text

To delete text in my file text we first move the cursor to end of that line and then press delete then the line is erased to do this first we open the file as  vi myfile.text The following commands allow you to delete text. Ø  x:- delete single character under cursor Ø  Nx:- delete N characters, starting with character under cursor Ø  dw:- delete the single word beginning with character under cursor Ø  dNw:-delete N words beginning with character under cursor; Ø  e.g., d5w deletes 5 words Ø  D:- delete the remainder of the line, starting with current cursor position Ø  dd:- delete entire current line Ø  Ndd or dNd:-delete N lines, beginning with the current line; e.g., 5dd deletes 5 lines

f.       Save the changes:

To save the changes made in file myfile.text we press esc:WQ It means that saves the file and quits editing mode then we log out from the vi  Mode.

Logout the system.

Syntax: exit Description: In our current directory press exit to log out from the commands

1. Log into the system
2. Use the ‘cat’ command to create a file containing the following data. Call it mytable use tabs to separate the fields.

3. Use the cat command to display the file, mytable.
4. Use the ‘vi’ command to correct any errors in the file, mytable.
5. Use the ‘sort’ command to sort the file my table according to the first field. Call the sorted file my table (same name)
6. Print the file mytable.
7. Use the cut and paste commands to swap fields 2 and 3 of mytable. Call it my table (Same name)
8. Print the new, my table.
9. Logout of the system

Log into the system

When we return on the system one screen will appear. In this we have to type 100.0.0.9 then we enter into editor. It asks our details such as          Login : krishnasai          password: Then we get log into the commands.

Use the cat command to create a file containing the following data. Call it mytable use tabs to separate the fields. 1425   Ravi     15.65 4320   Ramu   26.27 6830   Sita      36.15 1450   Raju     21.86

cat > mytable 1425   Ravi     15.65 4320   Ramu   26.27 6830   Sita      36.15             1450   Raju     21.86 To save the file press Ctrl + D or Ctrl+Z Description:- Cat Command can view the file data and create a new file and also concatenate file ü  Creating file Cat>file1.txt ü  Creating one file from several files cat file1 file2 file3 > file4 This command combines the contents of the first three files into file4. With this command, file4 is created if it didn't already exist. (Or, it will overwrite file4 if file4 already existed.) ü  Showing line numbers cat -n myfile.txt cat myfile -b This prints the line number before each line that is output ü  appending one file to another file cat file1>>file2 Append file1 at the end of the file2

Use the cat command to display the file, mytable.

$cat mytable 1425  Ravi  15.65 4320  Ramu  26.27 6830  Sita  36.15 1450  Raju  21.86

Use the vi command to correct any errors in the file ,mytable

By using vi editor we have to correct errors occurred in creating file . Open the file in vi editor as Syntax: Vi mytable Use vi command to correct errors

Use the sort command to sort the file mytable according to the first field. Call the sorted file my table

$sort +1 mytable > mytable Or $ sort  -k 1  mytable > sortfile;cp sortfile mytable Description:- Sort:- is a simple and very useful command which will rearrange the lines in a text file so that they are sorted, numerically and alphabetically. Syntax:  sort [OPTION]... [FILE]... Options Ø  -b, --ignore-leading-blanks      Ignore leading blanks. Ø  -d, --dictionary-order  Consider only blanks and alphanumeric characters. Ø-f, --ignore-case           Fold lower case to upper case characters. Ø  -g, --general-numeric-sort        Compare according to general numerical value. Ø  -i, --ignore-nonprinting            Consider only printable characters. Ø  -M, --month-sort         Compare (unknown) < `JAN' < ... < `DEC'. Ø  -h, --human-numeric-sort        Compare human readable numbers (e.g., "2K", "1G"). Ø  -n, --numeric-sort        Compare according to string numerical value. Ø  -R, --random-sort        Sort by random hash of keys. Ø  --random-source=FILE           Get random bytes from FILE. Ø  -r, --reverse      Reverse the result of comparisons. Ø  --sort=WORD Sort according to WORD: general-numeric -g, human-numeric -h, month -M, numeric -n, random -R, version -V. Ø  -V, --version-sort         Natural sort of (version) numbers within text. Note that this command does not actually change the input file, data.txt. If you want to write the output to a new file, output.txt, redirect the output like this: sort data.txt > output.txt You can perform a reverse-order sort using the -r flag. For example, the following command: sort -r data.txt

Print the file mytable

cat mytable 1425  Ravi   15.65 1450  Raju   21.86 4320  Ramu   26.27 6830  Sita       36.15

Use the cut and paste commands to swap fields 2 and 3 of mytable. Call it my table (same name)

$cut -f1 > mytab1 $ cut –f 2 > mytab 2 $cut –f 3 > my tab3 $paste mytab3 mytab2 > mytab4 $paste mytab1 mytab4 > mytable Description: Cut Remove or "cut out" sections of each line of a file or files. Syntax cut OPTION... [FILE]... Options Ø  -b, --bytes=LIST         Select only the bytes from each line as specified in LIST. LIST specifies a byte, a set of bytes, or a range of bytes; see Specifying LIST below. Ø  -c, --characters=LIST  Select only the characters from each line as specified in LIST. LIST specifies a character, a set of characters, or a range of characters; see Specifying LISTbelow. Ø  -d, --delimiter=DELIM           use character DELIM instead of a tab for the field delimiter. Ø  -f, --fields=LIST         select only these fields on each line; also print any line that contains no delimiter character, unless the -s option is specified. LIST specifies a field, a set of fields, or a range of fields; see Specifying LIST below. Ø  -n         This option is ignored, but is included for compatibility reasons. Ø  --complement  complement the set of selected bytes, characters or fields. Ø  -s, --only-delimited     do not print lines not containing delimiters. Ø  --output-delimiter=STRING   use STRING as the output delimiter string. The default is to use the input delimiter. To "cut" only the third field of each line, use the command: cut -f 3 data.txt If instead you want to "cut" only the second-through-fourth field of each line, use the command: cut -f 2-4 data.txt If you want to "cut" only the first-through-second and fourth-through-fifth field of each line (omitting the third field), use the command: cut -f 1-2,4-5 data.txt If you want the third field and every field after it, omitting the first two fields. In this case, you could use the command: cut -f 3- data.txt Specifying a range with LIST also applies to cutting characters (-c) or bytes (-b) from a line. For example, to output only the third-through-twelfth character of every line ofdata.txt, use the command: cut -c 3-12 data.txt paste command: The paste command displays the corresponding lines of multiple files side-by-side. Syntax: paste [OPTION]... [FILE]... Examples: paste file1.txt file2.txt This command would display the contents of file1.txt and file2.txt, side-by-side, with the corresponding lines of each file separated by a tab. $ cat file1 Linux Unix Solaris HPUX AIX paste command with a single file:  1. paste command without any options is as good as the cat command when operated on a single file. $ paste file1 Linux Unix Solaris HPUX AIX 2. Join all lines in a file: $ paste -s file1 Linux   Unix    Solaris HPUX    AIX -s option of paste joins all the lines in a file. Since no delimiter is specified, default delimiter tab is used to separate the columns. 3. Join all lines using the comma delimiter: $ paste -d, -s file1 Linux,Unix,Solaris,HPUX,AIX -d option is used to specify the delimiter. Using this -d and -s combination, all the lines in the file get merged into a single line.  4. Merge a file by pasting the data into 2 columns: $ paste - - < file1 Linux   Unix Solaris HPUX AIX The '-' reads a line from the standard input. Two '-' reads 2 lines and pastes them side by side. 5.Merge a file by pasting the data into 2 columns using a colon separator: $ paste -d':' - - < file1 Linux:Unix Solaris:HPUX AIX:         This is same as joining every 2 lines in a file. 6. Merge a file by pasting the file contents into 3 columns: $ paste - - - < file1 Linux   Unix    Solaris HPUX    AIX 7. Merge a file into 3 columns using 2 different delimiters: $ paste -d ':,' - - - < file1 Linux:Unix,Solaris HPUX:AIX, The -d option can take multiple de-limiters. The 1st and 2nd columns is separated by ':', whereas the 2nd and 3rd are separated by a ','. paste command examples for multiple files handling  Let us consider a file, file2, with the following contents: $ cat file2 Suse Fedora CentOS OEL Ubuntu 8. paste contents of 2 files side by side. $ paste file1 file2 Linux   Suse Unix    Fedora Solaris CentOS HPUX    OEL AIX     Ubuntu paste command is used in scenarios to merge multiple files side by side. As shown above, the file contents are pasted side by side.  9. paste contents of 2 files side by side with a comma separator: $ paste -d, file1 file2 Linux,Suse Unix,Fedora Solaris,CentOS HPUX,OEL AIX,Ubuntu 10. paste command can take standard input in case of multiple files too: $ cat file2 | paste -d, file1 - Linux,Suse Unix,Fedora Solaris,CentOS HPUX,OEL AIX,Ubuntu Like this as well: $ cat file1 | paste -d, - file2 Linux,Suse Unix,Fedora Solaris,CentOS HPUX,OEL AIX,Ubuntu One more: $ cat file1 file2 | paste -d, - - Linux,Unix Solaris,HPUX AIX,Suse Fedora,CentOS OEL,Ubuntu 11. Read lines in both the files alternatively: $ paste -d'\n' file1 file2 Linux Suse Unix Fedora Solaris CentOS HPUX OEL AIX Ubuntu

Print the new file, mytable

cat mytable 1425   15.65   Ravi 1450   21.86   Raju 4320   26.27   Ramu 6830   36.15   Sita

Logout the system.

Syntax: exit Description: In our current directory press exit to log out from the commands