Computational Techniques for Life Sciences

Miscellaneous Commands

Some say the only command you ever need to memorize is man. This command brings up the manual page for any other command. For exampe, try issuing:

$ man ls

Navigate the manual page by pressing <Enter> to scroll down line-by-line, or <Ctrl+u> or <Ctrl+d> to page up or page down. The q key or <Ctrl+c> can be used to exit. Take note of all the different flags that come with ls.

The commands echo and date will be useful later to print output control during batch job execution. For example, try the commands:

$ echo "The current date and time is:"
$ date

The which command tells the user the location of a command or program that is currently in the “PATH” (more on this later). For example, we can find the location of the ls command, or help determine the version of python that is in our PATH:

$ which ls
/bin/ls
$ which python
/usr/bin/python
$ python --version
Python 2.6.9

Finally, the history command prints your command line history. It is useful to scroll through previous commands:

$ history

Exercise

1. Use the date command to print the Coordinated Universal Time (UTC time zone).
2. Use the date command to just print the month.
3. What does the cal command do? Show some different examples.
4. What does the seq command do? Show some different examples.

Click here for solution

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