touch Command in Linux with Examples

DESCRIPTION

touch is a standard Unix program used to change a file’s access and modification timestamps. It is also used to create a new empty file.

SYNOPSIS

touch [-a] [-c] [-m] [-r ref_file | -t time ] file

OPTIONS :

-a
Change the access time of file. Do not change the modification time unless -m is also specified.
-c
Do not create a specified file if it does not exist. Do not write any diagnostic messages concerning this condition.
-m
Change the modification time of file. Do not change the access time unless -a is also specified.
-r
ref_file Use the corresponding times of the file named by ref_file instead of the current time.
-t
time Use the specified time instead of the current time. time will be a decimal number of the form:
[[CC]YY]MMDDhhmm [.SS]

MM – The month of the year [01-12].
DD – The day of the month [01-31].
hh – The hour of the day [00-23].
mm – The minute of the hour [00-59].
CC – The first two digits of the year.
YY – The second two digits of the year.
SS – The second of the minute [00-61].

-f
ref_file Use the corresponding times of the file named by ref_file instead of the current time.
file
A path name of a file whose times are to be modified.

EXAMPLES

1. The following touch command creates an empty (zero byte) new file called abc.

$ touch abc

2. By using touch command, you can also create more than one single file. For example the following command will create 3 files named, abc,def,ghi.

$ touch abc def ghi

3. To change or update the last access and modification times of a file called abc, use the -a option as follows. The following command sets the current time and date on a file. If the abc file does not exist, it will create the new empty file with the name.

$ touch -a abc

4. Using -c option with touch command avoids creating new files. For example the following command will not create a file called abc if it does not exists.

$ touch -c abc

5. If you like to change the only modification time of a file called abc, then use the -m option with touch command.

$ touch -m abc

6. You can explicitly set the time using -c and -t option with touch command. The following command sets the access and modification date and time to a file abc as 17:30 (17:30 p.m.) December 10 of the current year (2012).

$ touch -c -t 12101730 abc

7. The following touch command with -r option, will update the time-stamp of file abc with the time-stamp of def file. So, both the file holds the same time stamp.

$ touch -r abc def

8. If you would like to create a file with specified time other than the current time, then the below command touch command with -t option will gives the abc file a time stamp of 18:30:55 p.m. on December 10, 2012.

$ touch -t 201212101830.55 abc