File System Commands in Unix

This article aims to familiarize with the basic file system commands in Unix that helps to work with files and directories

touch command in Unix

The touch command is used to update the timestamps on existing files and directories as well as creating new, empty files.

• • • • Updates the access and modification times.
      • It is used to create a file without any content.
      • This command can be used when the user doesn’t have data to store at the time of file creation.

Syntax:

 touch [-amc] [mmddhhmm[yy]] files

 touch filename: When touch command is used without any options, if the file name specified as an argument doesn’t exist touch will create a new file.

touch -a file1: This command is used to change access time of file1.

touch file1 file2 file3 :Multiple files with name file1, file2 ,file3 are created at the same time

Examples of the cat command in Unix are:

1. 1. create or modify timestamp of file using touch command

touch file1

2. To create or modify multiple files at once, specify the file names as arguments

touch file1 file2 file3

dirname command in Unix

• • • • Strips non-directory suffix from filename

Syntax:

dirname NAME

dirname OPTION

for more details on dirname refer here

tar command in Unix

The tar command creates tar files by converting collection of files into an archive. It also can extract tar archives and display list of the files included in the archive.

• • • • Archiving files
      • File require archiving in order to compress data
      • Reduce the storage space.

Syntax:

tar [OPERATION_AND_OPTIONS] [ARCHIVE_NAME] [FILE_NAME(s)]

OPERATION: Only one operation argument is allowed and required. The most frequently used operations are: create (-c) – Create a new tar archive. extract (-x) – Extract the entire archive or one or more files from an archive. list (-t) – Displays list of the files included in the archive

ARCHIVE_NAME: The name of the archive.

FILE_NAME(s): A space-separated list of filenames to be extracted from the archive. If file name is not provided, the entire archive is extracted.

Example: 

1. 1. 1. 1. command creates a tar file called file.tar which is the Archive of all .dat files in the current directory.

$ tar -cvf file.tar *.c