touch
is one of those commands that I was introduced to rather flippantly. Just as a
consequence of following along with some blog.
touch
is a CLI utility that comes standard on most Unix-based OSes and like the name
implies;
touch
simply “touches” i.e creates files without requiring the user to directly
modify them. There is more to
touch
than simply making some quick example files for a tutorial as we will soon
see.
Basic touch usage
touch operates as follows:
touch -options filetocreate.txt
To create a new file, simply run the following:
touch filetotouch.txt
Just like that we have a brand new empty file! We can also create multiple files at once by separating the filenames with spaces:
touch filetotouch.txt filetotouch2.txt filetotouch3.txt
This can also be done more effectively using curly braces:
touch filetotouch{1..5}.txt
Advanced touch Usage
You might be under the impression that
touch
only creates files but the primary purpose of
touch is for timestamp manipulation! We can update the access and modification time
by calling
touch
on a file, this is the equivalent of passing
-a
(access) and
-m
(modification), if the file exists this will
not overwrite
the contents of the file. The timestamp will be updated to the current time.
touch filetotouch.txt
# or
touch -am filetotouch.txt
Obviously there are way more options available than I am providing here, but you can get more detail about them by running this hilarious command:
man touch.
-t
option and inputting the date we want in this format:
[[CC]YY]MMDDhhmm[.ss]. Below we are setting the date for Oct 31, 2017 at 12:30:56.
touch -t 201710311230.56 filetotouch.txt
ls -la: Note that in the time formatting above that the values in the square brackets are optional. For example we can omit the century, and just include the last 2 digits in the year or omit the year entirely and just use the current year, and finally the seconds can also be omitted
touch -t 1711241430 filetotouch2.txt
#or
touch -t 11241430 filetotouch3.txt
Of course, creating empty files is only so useful, how can we use touch in a meaningful way? Debugging! From working with scripts, to triggering file events for an app or simply creating placeholders for the future, touch
can be a handy tool. Now our empty files have a purpose!
Practical touch
inotifywait. For the sake of
brevity I won’t be covering the command in detail just yet, but it can be
installed with your package manager as
inotify-tools. After that I’ll make a sandbox directory and tell
inotifywait
to monitor it then open up a
tmux
section so we can see the monitor output side-by-side.
If you need a
tmuxrefresher check out our article here.
touch testfile.txt
touch
to create a dummy file that will trigger
inotifywait. We have now confirmed that we are monitoring the directory correctly.
A simple scenario, but it effectively illustrates the point.
A touching end
touch, a simple yet powerful tool that has broader uses than at first glance. From
creating empty files to modifying timestamps,
touch
can be incredibly useful in any users’ command wheelhouse. Thanks for reading
now go out there and
touch
some files!
