📌Highlights: In this post we know about the shell programming basic. This post cover so many basic commands which is useful in programming such as about editor ,type of mods , how deleting files, how cut/copy/paste file contents, how store in buffer, how find /replace files, how insert blank line in file.
➤ vi editor is used to write shell commands. vi editor is a text editor.vim editor is also used for shell programming.
➤ For opening vi editor we write
$ vi filename
Example : $ vi ab1
Now after this vi editor will open.
➤ Shell will run those command written with $ prompt.
➤ Shell has interpreter which will process step by step.
➤ We have two modes:
1. Command mode
2. Typing mode.
In command mode we write commands.
In typing mode we write typing text.
➤ Some symbol are used for command as well as contents of file such as:
( a-z | A-Z | φ-9 | & | $ )
⧭ Note :
➤ For switching command mode to typing mode press a.
➤ For switching typing mode to command mode press ESC key.
➤ For changing cursor position write:
n ( h j k l )
where:
n is number of moves.
h is for (←) left move.
j is for (↓) down move.
k is for (↑) up move.
l is for (→) right move.
Example:
20 h 20 move left.
20 j 20 move down.
20 k 20 move up.
20 l 20 move right.
They are only work in command mode.
⧭ For Deleting:
➤ x = For Deleting character from current character prompt (CCP).
➤ nx = For Delete n character
➤ dw = For Delete current word from CCP.
➤ ndw = For Delete n word.
➤ dd = For Delete lines from CCP.
➤ ndd = For Delete n line from CCP.
➤ U = For Undo the last command.
➤ . = For Repeat the last comand.
⧭ For Cut / Copy / Paste:
➤ p(small) is for Paste below.
➤ P(Capital) is for Paste above.
⧭ For Yanking:
It is used for storing in buffer.
➤ yy is yank
➤ nyy is yank n line from ccp lines.
➤ nyw is yank n words.
⧭ For Finding / Replace:
⧭ For Find:
➤ / string is used for search string in forward direction of current command prompt (CCP).
➤ n is used for continuous last search in same direction.
➤ N is used for continuous in opposite direction.
➤ ? string is used for search string in the backword direction of current command prompt (CCP)
⧭ For Replace:
➤ /s/string 1/string 2/g is used for forward direction.
where: string 1 is finding or searching string.
string 2 is replacing string.
➤ ? s ? string 1 ? string 2 is used for backward direction.
⧭ For Mode Command:
➤ wq is used write and quit
➤ q is used for quit
➤ r filename is used for read from fie.
➤ set nu is used to display line number.
➤ sh is used to go to operating system shell.
⧭ For inserting blank line between two lines:
O (Big / capital) is used to insert blank line above the CCP line.
This is the end of shell programming basic in unix part 1. In part 2 we will continue and know more about shell programming methodology that how to write programs.
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