Unix Command

**Basic Unix Command**

                  






  **Architecture of Unix**

                   
                








      
**Unix-command**

**Index of Commands**

cat - Display or concatenate files cd - change directory chmod -  change the permissions on a file or directory CP - copy a file date - display the current date and time diff - display differences between text files file - determine the type of a file find - find files of a specified name or type ftp - file transfer program grep - searches files for a specified string or expression gzip - compress a file help - display information about bash builtin commands info - read online documentation kill - kill a process lpr - print out a file ls - list names of files in a directory man - display an on-line manual page mkdir - make a directory more - scan through a text file page by page mv - move or rename files or directories nice - change the priority at which a job is being run passwd - change your password ps - list processes pwd - display the name of your current directory quota - disk quota and usage rm - remove files or directories rmdir - remove a directory sort - sort and collate lines ssh - secure remote access tar - create and use archives of files

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#cat - display or concatenate files

cat

 takes a copy of a file and sends it to the standard output (i.e. to be displayed on your terminal, unless redirected elsewhere), so it is generally used either to read files, or to string together copies of several files, writing the output to a new file.

cat ex




displays the contents of the file ex.

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#cd - change directory

cd

 is used to change from one directory to another.

cd dir1




changes directory so that dir1 is your new current directory. dir1 may be either the full pathname of the directory, or its pathname relative to the current directory.

cd




changes directory to your home directory.

cd ..




moves to the parent directory of your current directory.

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