I often find command line commands starting with dollar signs in instructions to install many things. For example to install Ruby in Ubuntu, the website says to use the following command:
$ sudo apt-get install ruby-full
What does the $ represent?
The $ is not part of the command. It's there to tell you that this command needs to be executed as a regular user.
When you prompt as a regular user (in bash shell at least), the line starts with the user name you're currently prompt as, followed by #, followed by the machine hostname, followed by :, followed by the current location, followed by $.
It looks like this :
bob#work-station:~$
But, if you prompt as root, the last $ will be replaced by a # :
root#work-station:~#
And that's the point of those tutorials :
If the command starts with $, you know that the command should be executed as regular user.
If it starts with #, it should be executed as root.
Hope it helps.
$ is not part of the command, it is just shown to illustrate terminal input. A full log of the guys entry would read something like
Dominic#stackoverflow$ sudo ap...
See the answer below https://stackoverflow.com/a/48215530/1117934, for a more complete explanation on the difference between $ and #.
Related
I have been trying to pip install psycopg2 for some time now
I have just updated to python 3.7.4, before this problem started.
To set my path to a specific python version I used the code below.
nano .bash_profile
I thought that it would now be easy for my system to identify the path of the newly installed python, as to enable it to install psycopg2. Then the below started happening.
The second line of system terminal or python terminal is now always showing:
-bash: zzzzz#: command not found on my terminal
No matter what I type on my terminal, I am always getting command not found
This would mean you literally have "zzzzz" somewhere in the bash_profile. Bash is seeing "zzzzz" as just another command to run at startup like the rest of the profile script. As there is nothing in your PATH matching that string, bash reports the issue back to you.
Either remove the extra line from your .bash_profile. OR use a terribly wasteful work-around!
ln -s /bin/true /bin/zzzzz
This will create a symbolic link to the "true" binary (all it ever does is return true) from zzzzz. Now bash can find zzzzz and run it during start up, which does nothing. No more error and an absurd work around. You should fix the file.
I am using a vpn service from certain server. I was given with a root account, and when I connect with a root account, the command line looks like below.
root#xa9g82:/etc/#
Then I used useradd to add an account called 'temp'
When I connected to the server with temp, then the command line only has a single character.
$
The user information is not shown, neither the path. Also, note that, in root's command line I can use tab to automatically complete the filename, however 'temp's command line inserts tab space, when I press tab. It is very inconvenient.
I am using Ubuntu 10.04. How can I resolve this issue?
I usually edit ~/.bashrc. Being root, you might want to change the system-wide preferences, at /etc/bash.bashrc. Personally, I changed some lines in ~/.bashrc to look like:-
# If this is an xterm set the title to user#host:dir
case "$TERM" in
xterm*|rxvt*)
## PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\u#\h: \w\a\]$PS1" # default
PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\h: \W\a\]$PS1" # How I like it
;;
*)
;;
esac
use prompt to set the prompt.... (man prompt...)
it depends on what shell you run each one has it's own tricks, but you can make it looks as you wish.
BASH
TCSH
It is likely that the default shell for root is set to /bin/sh, which does not provide many of the features that you may used to if you use a shell like bash. To check if this is the case, run the following command:
cat /etc/passwd | grep ^root
The last component of the line that this command outputs will be your shell (which, as stated previously, I'm guessing is /bin/sh). If this is not the shell you want (it probably isn't), then edit /etc/passwd (using nano or whatever editor you're most comfortable with) and change your shell to something more palatable, like /bin/bash. After doing this, you'll need to log out and then log back in.
As this post points out you can install Vimballs using the normal:
vim somevimball.vba
:so %
:q
But if you want to install a from the command line how do you do it? I ran a 'man vim' and it seems like the best "from source install" option was the '-S' option so I tried to install haskellmode with it:
wget 'http://projects.haskell.org/haskellmode-vim/vimfiles/haskellmode-20090430.vba'
vim -S haskellmode-20090430.vba
and that failed to work. It gave me the following error:
Error detected while processing function vimball#Vimball:
line 10:
(Vimball) The current file does not appear to be a Vimball!
press ENTER or type command to continue
It should be noted that using the first method I was able to successfully install the vimball. I have tried the second method on a few other vimballs and it has failed every time. Is there a way to install a vimball from the command line? It seems like a useful sort of task.
Oh, and I am running the following version of vim:
Version: 2:7.2.330-1ubuntu3
Thanks.
Use one of the following commands:
vim -c 'so %' -c 'q' somevimball.vba
or:
vim -c 'so % | q' somevimball.vba
For more information, see:
:help -c
:help :bar
Having seen this solution I decided to hide the messiness in a script that always should have existed, vim-install: http://github.com/robertmassaioli/vim-install
Today's Daily Vim says this:
Assuming you're using the bash shell, the following can be helpful when composing long command lines.
Start typing on the command line and then type Ctrl-x Ctrl-e, it should drop you into your system's default editor (hopefully Vim) and allow you to edit the command line from there. Once finished, save the command line, and bash will run the command.
Is there any way to do this in tcsh?
A little explanation for the uninitiated.
bindkey -v
puts you in vi-mode (oh yeah!)
and hitting v from there would take you to $EDITOR -- and all is good with the world from there on.
Hmmm... IIRC, tcsh uses a command called bindkey. Try bindkey -v at the command line. Then hit escape followed by v. It's been a while since I used tcsh so the details are a bit fuzzy. When in doubt, Google it.
When working on a linx CShell u get the option to press the up / down arrows to select the last command/s typed or the Command Buffer. This even works on Windows.
However this is not functional when working on Solaris, to which i recently switched. I am guessing that the shell is also a CShell.
Please tell me what key combination is required to have this feature on Solaris ?
The default shell in Solaris has command history, but you can also use Bash instead, it's more user friendly. Just type 'bash' (no quotes) at the command line. You can also edit /etc/passwd to make bash your default shell.
The "official" default shell for Solaris is actually sh, the original Bourne shell (see Chapter 10 of the Advanced User Guide for Solaris for more info). If you'd like to change it to csh or tcsh—and you're not root (it's generally considered bad practice to use anything but sh as root's default)—just issue passwd -e /path/to/shell_of_your_choice <loginname>. I'm guessing this would probably look like passwd -e /bin/csh <loginname>, but you'd probably want to make sure it exists, first.
It may be that it's the Korn shell in which case try <ESC>k.
bash at least will allow you to switch modes with "set -o vi" or "set -o emacs".
Maybe you can use the !! command, to repeat the previous one.
Use "echo $SHELL" to see what your login shell is. If it's ksh or bash, try "set -o emacs". If that works, you'll be able to use ^P to go back a command. ^R lets you search for a command, ^F and ^B to move around within the command.
If you can´t change your default shell, or you just want to try out one that works, you can kick off any other shell from your command line. I recommend you tcsh, which will have good command line editing and history using the arrow keys. Type /bin/tcsh at your prompt to try it out. You can use the earlier responses to change your default shell if you like tcsh. Make sure your have the following in your $HOME/.cshrc file:
set filec
set history=1000 # or some other large number
set autologout=0 # if you are logging in remotely under your account.
I hope this helps.
You enable history temporarily if you use BASH by typing
HISTSIZE=1000
which will enable up and down keys and store 1000 commands. After termal disconnetion all history will be gone.
This works on solaris 10.
For permanent solution add these lines to ~/.bashrc
HISTSIZE=1000
HISTFILESIZE=1000