For running direct commands, there are two ways.
- Either run in Terminal
- Or run from the "Run Command" dialogue (screen shown below) obtained from Alt+F2
Then, Is there any difference between them? (working same & shell) or redirects to same?
Ubuntu – ny difference between run command in terminal & ALT+F2
command lineexecute-commandunity
Related Solutions
With the first method you are not creating an alias, you are creating a symlink. Symlinks are short for symbolic links:
Symbolic links are files that act as pointers to other files. [...] A symbolic link is a special type of file whose contents are a string that is the pathname another file, the file to which the link refers. In other words, a symbolic link is a pointer to another name, and not to an underlying object.
Read more about symlinks here and here.
Only with the second method you are, in fact, creating an alias.
Aliases allow a string to be substituted for a word when it is used as the first word of a simple command. The shell maintains a list of aliases that may be set and unset with the alias and unalias builtin commands (see SHELL BUILTIN COMMANDS below). The first word of each simple command, if unquoted, is checked to see if it has an alias. If so, that word is replaced by the text of the alias.
You can define an alias anywhere where you can type a command and have the shell (bash in this case) interpret it, however in order for the alias to be available in other shells it needs to be defined in a file that's interpreted by the shell on startup (shell startup, not computer startup).
For bash these are /etc/bash.bashrc (system wide) and ~/.bashrc. These files are interpreted when the shell starts in interactive mode (like when using Terminal). I'm not going to mention the profile files because they serve a different purpose.
So, you want to add your aliases to ~/.bashrc to have them available in every interactive shell.
The .bash_aliases method accomplishes exactly the same thing as putting the aliases in ~/.bashrc but has the added benefit of being easier to be parsed and manipulated by programs.
The . ~/.bash_aliases means source (load) _~/.bash_aliases_ in the context of the currently running shell.
If you are referring to RAM usage, it is because system monitor does not include buffers and caching, just actual Ram used to run applications, top is slightly confusing because it does not obviously show disk usage after buffers / caching. Try using the following command :
free -m
See the image below, and note that the second line of free -m indicates available Ram, whilst the first line indicates actual Ram usage including disk caching.
I would recommend installing and using htop as it is better and simpler than top in my opinion.
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Best Answer
I don't think there is any difference between the two it's just that once you run a command using Alt + F2 the dash closes before you see the results / output. But it is used according to different purpose as following.
Use Alt + F2 when running commands that expected no output or that open an external application. Example:
gksu nautiluswhich opens up a root nautilus window.For commands that expected an output -
ls,rm,find,update,upgrade,install, etc then recommended to use the terminal.