Touch command in Linux

Touch command in Linux is used for changing file timestamps however one of the most common usages of touch command includes creating a new empty file.

With the touch command, you can change access, modify and change time of files and folders in Linux. You can update the timestamps or modify them to a date in the past.

The syntax for touch command is quite simple:

touch [option] file

I have written about timestamps in Linux in detail in an earlier article. I would recommend reading it for a better and clearer understanding. For the sake of a quick recall, I’ll list the timestamps here:

access time – last time when a file was accessed

modify time – last time when a file was modified

change time – last time when file metadata (file permission, ownership etc) was changed

You can see the timestamps of a file using the stat command in the following manner:

stat abhi.txt File: abhi.txt Size: 10 Blocks: 8 IO Block: 4096 regular file Device: 10305h/66309d Inode: 11940163 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 1000/abhishek) Gid: ( 1000/abhishek) Access: 2018-09-02 14:12:24.476483367 +0530 Modify: 2018-09-02 14:12:24.476483367 +0530 Change: 2018-09-02 14:12:24.476483367 +0530 Birth: -

Stat command even shows the inode number of the file.

9 Practical examples of touch command in Linux

Now let’s see how to use the touch command with some simple but useful examples.

1. Create an empty file

As I mentioned earlier, this is the most common use of touch command. All you have to do is to use touch with the file name.

touch <filename>

This will create an empty file if the file doesn’t exist.

touch empty_file ls -l empty_file -rw-r--r-- 1 abhishek abhishek 0 Sep 2 14:37 empty_file

But what if the file already exists? In that case, it will update all three timestamps of the file to the current time.

2. Create multiple empty files

You can use touch to create more than one empty file as well. Just provide the names of the files you want to create.

touch <file1> <file2> <file3>

If you think it’s tiring to write all filenames, you can auto-generate filenames in this way:

touch new-file-{1..10}.txt

This will create new-file-1.txt, new-file-2.txt upto new-file-10.txt.

3. Avoid creating a file with touch if it doesn’t exist

Touch will update the timestamps of input file if it exists and will create an empty file if the input file does not exist.

But what if you don’t want touch to create a new empty file? You want it to update the timestamps of the file but if the file doesn’t exist, it should not be created.

You can use the touch command with -c option in such cases:

touch -c <filename>

Remember: Touch will create a new empty file if it doesn’t exist else it will modify the timestamps of the existing file. You can stop the creation of a new file with the -c option.

If you use touch on an existing file, it will change access, modify and change time of that file.

For example, I have this file named sherlock.txt with the following timestamps:

stat sherlock.txt File: sherlock.txt Size: 356 Blocks: 8 IO Block: 4096 regular file Device: 10305h/66309d Inode: 11928277 Links: 1 Access: (0777/-rwxrwxrwx) Uid: ( 1000/abhishek) Gid: ( 1000/abhishek) Access: 2018-08-25 09:44:56.092937000 +0530 Modify: 2018-08-09 09:41:05.028309000 +0530 Change: 2018-08-25 09:44:56.096937182 +0530

If I use touch on this command, all timestamps will be changed to the current timestamps.

touch sherlock.txt stat sherlock.txt File: sherlock.txt Size: 356 Blocks: 8 IO Block: 4096 regular file Device: 10305h/66309d Inode: 11928277 Links: 1 Access: (0777/-rwxrwxrwx) Uid: ( 1000/abhishek) Gid: ( 1000/abhishek) Access: 2018-09-02 15:22:47.017037942 +0530 Modify: 2018-09-02 15:22:47.017037942 +0530 Change: 2018-09-02 15:22:47.017037942 +0530 Birth: -

Note: You should not be bothered with ctime (change time). It’s a system property and cannot/shouldn’t be controlled by the user. Your focus should be on access and modify time.

You may not always want to change all the timestamps of a file. If you just want to change the access time of a file, you can use the -a option with touch.

touch -a sherlock.txt stat sherlock.txt File: sherlock.txt Size: 356 Blocks: 8 IO Block: 4096 regular file Device: 10305h/66309d Inode: 11928277 Links: 1 Access: (0777/-rwxrwxrwx) Uid: ( 1000/abhishek) Gid: ( 1000/abhishek) Access: 2018-09-02 15:29:08.796926093 +0530 Modify: 2018-09-02 15:22:47.017037942 +0530 Change: 2018-09-02 15:29:08.796926093 +0530 Birth: -

If you just want to update the modify time of a file to the current timestamp, use the -m option of touch command.

touch -m sherlock.txt stat sherlock.txt File: sherlock.txt Size: 356 Blocks: 8 IO Block: 4096 regular file Device: 10305h/66309d Inode: 11928277 Links: 1 Access: (0777/-rwxrwxrwx) Uid: ( 1000/abhishek) Gid: ( 1000/abhishek) Access: 2018-09-02 15:29:08.796926093 +0530 Modify: 2018-09-02 15:31:25.770866881 +0530 Change: 2018-09-02 15:31:25.770866881 +0530 Birth: -

You can also use the timestamps of another file as a reference with the -r option in the following manner:

touch -r <source_file> <target_file>

This will set the access and modify time of the target file same as the access and modify time of the source file.

8. Set specific access and modification time

You might have noticed that in almost all the cases (except the reference file one), the timestamps are changed to the current timestamp.

But you are not bound with that. Touch allows you to set access and modification time to a past or future date. You can use the -t option and a timestamp in the following format:

[[CC]YY]MMDDhhmm[.ss]

CC – First two digits of a year

YY – Second two digits of a year

MM – Month of the year (01-12)

DD – Day of the month (01-31)

hh – Hour of the day (00-23)

mm – Minute of the hour (00-59)

ss – Seconds (00-59)

In the above case, CC is optional. In fact, CCYY is optional as well, it will take the current year in that case. Similarly, seconds are optional as well, it defaults to 00.

Let me show you an example by changing the timestamp to 12021301 i.e., 12th month, second day, 13th hour and first minute of the current year:

touch -t 12021301 agatha.txt stat agatha.txt File: agatha.txt Size: 457 Blocks: 8 IO Block: 4096 regular file Device: 10305h/66309d Inode: 11928279 Links: 1 Access: (0777/-rwxrwxrwx) Uid: ( 1000/abhishek) Gid: ( 1000/abhishek) Access: 2018-12-02 13:01:00.000000000 +0530 Modify: 2018-12-02 13:01:00.000000000 +0530 Change: 2018-09-02 15:59:47.588680901 +0530 Birth: -

If you try to enter an invalid date, you’ll see an error. You’ll also notice that change time is using the current timestamp, not the same as access and modify. It’s because it’s system property.

You can also use touch command with symbolic links. You just have to use the -h option while dealing with symbolic links. The rest stays the same as the regular files.

touch -h <symbolic_link>

I hope you find these touch command examples in Linux helpful. If you have any questions or suggestions, do let me know.