The date and time displayed by
ls -l can be changed to any format you want.
The default is:
$ ls -l
-rw-rw-r-- 1 joe joe 6 Jan 27 12:23 a.txt
-rw-rw-r-- 1 joe joe 522 Jan 27 12:22 haha.txt
-rw-rw-r-- 1 joe joe 80360 Jan 27 12:23 jump.pdf
To change the format of the date and time use the
--time-style option. Values that can be passed to it are
iso. You can also specify your own custom format as a string.
Here is how the different time styles look:
$ ls -l --time-style=long-iso
-rw-rw-r-- 1 joe joe 6 2015-01-27 12:23 a.txt
-rw-rw-r-- 1 joe joe 522 2015-01-27 12:22 haha.txt
-rw-rw-r-- 1 joe joe 80360 2015-01-27 12:23 jump.pdf
$ ls -l --time-style=full-iso
-rw-rw-r-- 1 joe joe 6 2015-01-27 12:23:08.309375574 +0800 a.txt
-rw-rw-r-- 1 joe joe 522 2015-01-27 12:22:59.773375414 +0800 haha.txt
-rw-rw-r-- 1 joe joe 80360 2015-01-27 12:23:32.693376032 +0800 jump.pdf
$ ls -l --time-style=iso
-rw-rw-r-- 1 joe joe 6 01-27 12:23 a.txt
-rw-rw-r-- 1 joe joe 522 01-27 12:22 haha.txt
-rw-rw-r-- 1 joe joe 80360 01-27 12:23 jump.pdf
Tried with: Ubuntu 14.04
In C++11 and later versions, date and time is supported in the standard library through the
chrono header file. To print out the date and time, you may still have to fall back on the
std::tm structures and
std::localtime functions from the
ctime header file and
iomanip header file.
The code sample below shows these in action:
Tried with: Visual C++ 2013
The easiest way to obtain the date and time string in C++ is to use time, localtime_s and asctime_s. The output string is of the form
Tue Aug 02 15:11:23 2011.
Here is the self-explanatory code:
struct tm locTime;
const int TimeStrLen = 26;
char timeStr[ TimeStrLen ];
if ( ( -1 != time( &curTime ) ) // Seconds since 01-01-1970
&& ( 0 == localtime_s( &locTime, &curTime ) ) // Convert to local time
&& ( 0 == asctime_s( timeStr, TimeStrLen, &locTime ) ) // Convert to string
cout << "Date-time is: " << timeStr;
cerr << "Error calculating date-time!" << endl;
exit( 1 );
The Clock on the Panel in Ubuntu displays the time. You can enable it to display the date and day of the week by changing its settings. It displays this information in this format:
Fri Apr 2 02:10 PM
I prefer the following format for date and time display:
2010-04-02 Fri 14:10
The date and time format can be changed to anything that you are comfortable with.
Ubuntu 12.04 and later
Changing date-time format in Ubuntu
Here is how to change the date and time format of the panel clock to your liking:
- Install the package dconf-tools from the Ubuntu repositories. This installs the dconf-editor which is needed for changing the configuration.
Open dconf editor from the Dash or dconf-editor from the shell. In the editor, navigate to com.canonical.indicator.datetime.
Change the time-format field to custom.
In the custom-time-format field, change the value to the desired format. The format can include both the date and time specifiers. This format uses the same specifiers as that of the C standard library function
To change to my desired format, I use:
%Y-%m-%d %a %H:%M
2010-04-02 Fri 14:10
The changes should take effect immediately and the date-time should change in the panel.
Tried with: Ubuntu 12.04 and Ubuntu 14.04
Ubuntu 10.04 and older
Use gconf-editor. Navigate to
/apps/panel/applets/clock_screen0/prefs. Change format field to the string custom. Change the custom_format field as described above.