How to show the host name in Linux commandline prompt
I have several VMs and right now my command-line prompt looks like -bash-3.2$ ; identical on every VM, because it doesn’t contain the host name. I need to always see which VM I’m on using hostname before I do any operation. How can I add the host name to the shell prompt? ENV: CentOS/ssh
I always use a prompt where I can easily copy it for a scp-command, so it is export PS1=’\u@\h:\w \$ ‘ .
4 Answers 4
Look into your ~/.bashrc or ~/.profile , there may be a commented prompt setup that should do what you want, like this one on our infra:
Or if you plan on logging as non-root, you can use:
to add username before the hostname.
You can have fun adding colours, multiline or whatever info you want in the prompt, a quick search on «bash prompts» should give you plenty of hints.
Just change the value of the $PS1 environment variable:
where \h is replaced with the hostname. Add that to /etc/bash.bashrc to set it permanent.
I like when the shell prompt shows the username, hostname and the name of the working directory. In addition, I like, when all of this is shown in colors. So I usually put
export PS1='\[\033[0;32m\]\u@\h:\[\033[36m\]\W\[\033[0m\] \$ ' in ~/.bashrc . In order to apply changes immediately, call
Also if you switch to root using su it is good to see bash prompt in a different color, so that you exercise extra caution. For this I add the line
export PS1='\[\033[0;31m\]\u@\h:\[\033[36m\]\W\[\033[0m\] \$ ' into /root/.bashrc . And call
to apply the changes. Then it looks like this
Very often VPS server admins provide dumb hostnames. In order to change it, open /etc/sysconfig/network and change the line
HOSTNAME=put_a_name_that_you_want_to_see_in_bash_prompt_here If you want different colors for username@host part, you have to change 0;32m part in the first example, or 0;31m part in the second example. The list of available colors can be found here
Since .bashrc is executed for non-login shells, do not forget to double check that
if [ -f ~/.bashrc ]; then . ~/.bashrc fi is present in ~/.bash_profile , since ~/.bash_profile is executed at your login. And also add the same piece into /root/.bash_profile .
Getting Hostname in Bash in Linux in 3 Ways
Getting the hostname of the node running a program can be useful in various scenarios, such as creating logs with the hostname, identifying which node a script is running on, or configuring a distributed system with different nodes. In Bash, there are several ways to retrieve the hostname of the machine, as mentioned in the previous post.
In Bash, you can get the hostname of the node in at least 3 ways:
Use the variable $HOSTNAME
The first method is to use the $HOSTNAME variable, which is a Bash environment variable that contains the name of the current hostname. This variable is set by the Bash shell at startup and can be accessed by any Bash script. However, it is worth noting that the value of $HOSTNAME may not always match the actual hostname of the machine, especially if the variable is manually set or modified.
Use the hostname command
The second method is to use the hostname command, which is a utility that retrieves and sets the hostname of the machine. When invoked without any arguments, the hostname command prints the current hostname of the machine to the standard output. This method is useful when you need to retrieve the hostname from within a script and store it in a variable for further processing.
$ hs=`hostname` $ echo $hs host01Read the content of the Linux kernel /proc/sys/kernel/hostname file
The third method is to read the content of the /proc/sys/kernel/hostname file, which contains the current hostname of the machine. This method is similar to using the hostname command, but it reads the hostname from a system file instead of invoking a command. This method is useful when you need to quickly retrieve the hostname from the command line without invoking a command.
$ cat /proc/sys/kernel/hostname host01Linux hostname in bash
NAME
hostname - show or set the system's host name domainname - show or set the system's NIS/YP domain name ypdomainname - show or set the system's NIS/YP domain name nisdomainname - show or set the system's NIS/YP domain name dnsdomainname - show the system's DNS domain name
SYNOPSIS
hostname [-a|--alias] [-d|--domain] [-f|--fqdn|--long] [-A|--all-fqdns] [-i|--ip-address] [-I|--all-ip-addresses] [-s|--short] [-y|--yp|--nis] hostname [-b|--boot] [-F|--file filename] [hostname] hostname [-h|--help] [-V|--version] domainname [nisdomain] [-F file] ypdomainname [nisdomain] [-F file] nisdomainname [nisdomain] [-F file] dnsdomainname
DESCRIPTION
Hostname is used to display the system's DNS name, and to display or set its hostname or NIS domain name. GET NAME When called without any arguments, the program displays the current names: hostname will print the name of the system as returned by the gethostname(2) function. domainname will print the NIS domainname of the system. domainname uses the gethostname(2) function, while ypdomainname and nisdomainname use the yp_get_default_domain(3). dnsdomainname will print the domain part of the FQDN (Fully Qualified Domain Name). The complete FQDN of the system is returned with hostname --fqdn (but see the warnings in section THE FQDN below). SET NAME When called with one argument or with the --file option, the commands set the host name or the NIS/YP domain name. hostname uses the sethostname(2) function, while all of the three domainname, ypdomainname and nisdomainname use setdomainname(2). Note, that this is effective only until the next reboot. Edit /etc/hostname for permanent change. Note, that only the super-user can change the names. It is not possible to set the FQDN or the DNS domain name with the dnsdomainname command (see THE FQDN below). The host name is usually set once at system startup in /etc/init.d/hostname.sh (normally by reading the contents of a file which contains the host name, e.g. /etc/hostname). THE FQDN The FQDN (Fully Qualified Domain Name) of the system is the name that the resolver(3) returns for the host name, such as, ursula.example.com. It is usually the hostname followed by the DNS domain name (the part after the first dot). You can check the FQDN using hostname --fqdn or the domain name using dnsdomainname. You cannot change the FQDN with hostname or dnsdomainname. The recommended method of setting the FQDN is to make the hostname be an alias for the fully qualified name using /etc/hosts, DNS, or NIS. For example, if the hostname was "ursula", one might have a line in /etc/hosts which reads 127.0.1.1 ursula.example.com ursula Technically: The FQDN is the name getaddrinfo(3) returns for the host name returned by gethostname(2). The DNS domain name is the part after the first dot. Therefore it depends on the configuration of the resolver (usually in /etc/host.conf) how you can change it. Usually the hosts file is parsed before DNS or NIS, so it is most common to change the FQDN in /etc/hosts. If a machine has multiple network interfaces/addresses or is used in a mobile environment, then it may either have multiple FQDNs/domain names or none at all. Therefore avoid using hostname --fqdn, hostname --domain and dnsdomainname. hostname --ip-address is subject to the same limitations so it should be avoided as well.
OPTIONS
-a, --alias Display the alias name of the host (if used). This option is deprecated and should not be used anymore. -A, --all-fqdns Displays all FQDNs of the machine. This option enumerates all configured network addresses on all configured network interfaces, and translates them to DNS domain names. Addresses that cannot be translated (i.e. because they do not have an appropriate reverse IP entry) are skipped. Note that different addresses may resolve to the same name, therefore the output may contain duplicate entries. Do not make any assumptions about the order of the output. -b, --boot Always set a hostname; this allows the file specified by -F to be non-existant or empty, in which case the default hostname localhost will be used if none is yet set. -d, --domain Display the name of the DNS domain. Don't use the command domainname to get the DNS domain name because it will show the NIS domain name and not the DNS domain name. Use dnsdomainname instead. See the warnings in section THE FQDN above, and avoid using this option. -f, --fqdn, --long Display the FQDN (Fully Qualified Domain Name). A FQDN consists of a short host name and the DNS domain name. Unless you are using bind or NIS for host lookups you can change the FQDN and the DNS domain name (which is part of the FQDN) in the /etc/hosts file. See the warnings in section THE FQDN above und use hostname --all- fqdns instead wherever possible. -F, --file filename Read the host name from the specified file. Comments (lines starting with a `#') are ignored. -i, --ip-address Display the network address(es) of the host name. Note that this works only if the host name can be resolved. Avoid using this option; use hostname --all-ip-addresses instead. -I, --all-ip-addresses Display all network addresses of the host. This option enumerates all configured addresses on all network interfaces. The loopback interface and IPv6 link-local addresses are omitted. Contrary to option -i, this option does not depend on name resolution. Do not make any assumptions about the order of the output. -s, --short Display the short host name. This is the host name cut at the first dot. -V, --version Print version information on standard output and exit successfully. -y, --yp, --nis Display the NIS domain name. If a parameter is given (or --file name ) then root can also set a new NIS domain. -h, --help Print a usage message and exit.
NOTES
FILES
/etc/hostname Historically this file was supposed to only contain the hostname and not the full canonical FQDN. Nowadays most software is able to cope with a full FQDN here. This file is read at boot time by the system initialization scripts to set the hostname. /etc/hosts Usually, this is where one sets the domain name by aliasing the host name to the FQDN.
AUTHORS
Peter Tobias, tobias@et-inf.fho-emden.de> Bernd Eckenfels, net-tools@lina.inka.de> (NIS and manpage). Michael Meskes, meskes@debian.org>