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Most Common UNIX Commands Part - I

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As we know we have pretty good number of commands with umpteen options.We will see most command commands which we use in our daily work.

CAT v/s MORE:

Both CAT & MORE command are primarily used to view the files the difference being that CAT command opens the complete file in a single shot however MORE command opens the file with respect to screen size i.e. if the file is huge we need to hit "space/enter" button to proceed.

CAT command is also used to append,create file.

cat>file name: Creates file if not present, if present then overrides the data. If we need to append the data then cat>>filename then ctrl+D to save the changes

echo$0 to find the current shell

ls -lrt will list all the files in a current directory with respect to timestamp

ls -a will list all the hidden files

ls -lrt | grep '^d' will list out all the directories in a current location

gunzip filename this is used for zipping the file for example gz b2.txt will give output as b2.txt.gz

For unzipping gunzip b2.txt.gz

wc -l filename to find the number of lines in a file. wc -c to find number of characters.

grep - global regular expression patten search this is one of the most command which we would be using

grep string filename for eg grep aa filename.txt will return all the string's which has 'aa' in them.

grep -v string filename would work in viceversa i.e. if we give grep -v aa filename.txt it will return all the string which doesn't have 'aa' in them.

To run a command in back ground we have to give "&" at the end of the statement.We go for background when we are sure that a given command will take lot of time to complete then we can move the command to background and in the mean time we can proceed with other works on terminal

for eg cat filename &

To bring the command to foreground then fg enter

Cut command is used to extract a column from a file.

cut -d ',' -f1 filename in here -d is used to represent the delimiter and -f1 represents first column f2 means second and so on.

cd ~ is used to go to home directory

cd .. is used to go one step back kind of up button in windows OS

cd -- is used to previous directory kind of back button in windows OS

who username is used to find the details of users.

ps to list out all the active process.

Now I'm gonna put a stop on this article or else it would start looking like a never ending speech.
we would be posting more unix commands in our coming articles.

Hope this articles helps you in understanding basic UNIX commands

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