What is touch?
3 touch examples
Syntax and Options
Related Commands
What is touch?
touch command is used to change the timestamp of a file.
3 touch Examples
1. Change access, modify, and change timestamp to current timestamp
In the following example, file f1.c has different timestamps for the access, modification and change.
$ stat f1.c File: `f1.c' Size: 59 Blocks: 8 IO Block: 4096 Regular File Device: 301h/769d Inode: 280971 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2010-11-01 19:07:50.000000000 +0530 Modify: 2009-07-21 17:20:36.000000000 +0530 Change: 2009-07-21 17:20:36.000000000 +0530
When you touch the file as shown below, it will change all timestamps (access, modify and change) to current timestamp.
$ touch f1.c $ stat f1.c File: `f1.c' Size: 59 Blocks: 8 IO Block: 4096 Regular File Device: 301h/769d Inode: 280971 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2010-11-01 20:35:58.000000000 +0530 Modify: 2010-11-01 20:35:58.000000000 +0530 Change: 2010-11-01 20:35:58.000000000 +0530
2. Change access and modification time to particular timestamp
The following example changes the access and modify timestamp to 15th June 13:30 using touch -t option.
Format for touch -t is : [[CC]YY]MMDDhhmm[.ss]
# touch -t 06151330 f1.c # stat f1.c File: `f1.c' Size: 59 Blocks: 8 IO Block: 4096 Regular File Device: 301h/769d Inode: 280971 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2010-06-15 13:30:00.000000000 +0530 Modify: 2010-06-15 13:30:00.000000000 +0530 Change: 2010-11-01 20:43:59.000000000 +0530
Note: You cannot modify the “Change” time, as it will be set to the current time as the inode change time is current time.
3. Change only the modification time using touch -m
To update only the modification time of a file, use touch -m option along with the above explained -t option, as shown in the example below.
$ touch -m -t 08210820 f1.c $ stat f1.c File: `f1.c' Size: 59 Blocks: 8 IO Block: 4096 Regular File Device: 301h/769d Inode: 280971 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2010-06-15 13:30:00.000000000 +0530 Modify: 2010-08-21 08:20:00.000000000 +0530 Change: 2010-11-01 20:45:05.000000000 +0530
Note: In the same way you can use touch -a option (along with touch -t option) to change only the access time for the file.
Syntax and Options
| Short Option | Long Option | Option Description |
|---|---|---|
| -a | change only the access time | |
| -B | –backward=SECONDS | Modify the time by going back SECONDS seconds. For example, touch -r foo -B 5 bar will make the file bar 5 seconds older than file foo. |
| -c | –no-create | do not create any files |
| -d | –date=STRING | parse STRING and use it instead of current time |
| -F | –forward=SECONDS | Modify the time by going forward SECONDS seconds. |
| -m | change only the modification time | |
| -r | –reference=FILE | use this file’s times instead of current time |
| –time=WORD | set time given by WORD: access atime use (same as -a) modify mtime (same as -m) |
Comments on this entry are closed.
Hi,The information is excellent.I learned touch command within a single read of it.