Path in linux shell

What is this $PATH in Linux and how to modify it

Yes, you can change it — for example add to the $PATH folder with your custom scripts.

So: if your scripts are in /usr/local/myscripts to execute them you will have to type in a full path to the script: /usr/local/myscripts/myscript.sh After changing your $PATH variable you can just type in myscript.sh to execute script.

Here is an example of $PATH from RHEL:

To change your $PATH you have to either edit ~/.profile (or ~/.bash_profile ) for user or global $PATH setting in /etc/profile .

One of the consequences of having inaccurate $PATH variables is that shell will not be able to find and execute programs without a full $PATH .

Oh my God, you clarified it all for me by your statement —> «So: if your scripts are in /usr/local/myscripts to execute them you will have to type in a full path to the script: /usr/local/myscripts/myscript.sh After changing your $PATH variable you can just type in myscript.sh to execute script.» Thanks a lot

@ruggedbuteducated just bash commands which are executed after you log in. Please look into man bash and search for bashrc.

Firstly, you are correct in your statement of what $PATH does. If you were to break it somehow (as per your third point), you will have to manually type in /usr/bin/xyz if you want to run a program in /usr/bin from the terminal. Depending on how individual programs work, this might break some programs that invoke other ones, as they will expect to just be able to run ls or something.

So if you were to play around with $PATH, I would suggest saving it somewhere first. Use the command line instruction

echo $PATH > someRandomFile.txt 

to save it in someRandomFile.txt

You can change $PATH using the export command. So

HOWEVER, this will completely replace $PATH with someNewPath. Since items in path are separated by a «:», you can add items to it (best not to remove, see above) by executing

The fact that it is an environmental variable means that programs can find out its value, ie it is something that is set about the environment that the program is running in. Other environmental variables include things like the current directory and the address of the current proxy.

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Shell how to get a path in linux

We can use this command to get the path of a Linux command: This shows that when we call the docker command, it will run the Docker executable file in the /usr/bin/ directory. » Solution 2: Instead of the command, use the variable (it’s in POSIX as well): If you need to support Windows, recognizing absolute paths will be more complicated as each port of unix tools has its own rules for translating file paths.

How to get the full path of a file in bash?

On linux systems, you should have readlink from the GNU coreutils project installed and can do this:

Debian/ubuntu systems may have the realpath utility installed which «provides mostly the same functionality as /bin/readlink -f in the coreutils package.»

Instead of the pwd command, use the PWD variable (it’s in POSIX as well):

If you need to support Windows, recognizing absolute paths will be more complicated as each port of unix tools has its own rules for translating file paths. With Cygwin, use the cygpath utility.

Printing directory path without file name, echo «$» is a built-in substitution: that would be much faster than a new dirname process for every name. – Paul_Pedant

Everything You Need to Know About $PATH in Bash

How does PATH work in Linux? How does Linux know where to look for the commands that you
Duration: 9:31

Get the Full Path of a File in Linux

1. Overview

Files and directories are building blocks of an operating system. As Linux users, we perform a variety of operations on the files and directories. One such operation is finding a full path of a file. The full path of a file is also known as its absolute or canonical path.

In this tutorial, we’ll discuss various ways to find the full path of a file.

2. Setup

Let’s create files and directories structure to use as an example:

$ cd /tmp $ mkdir -p dir1/dir2/dir3/dir4/dir5 $ touch dir1/dir2/file2.txt $ touch dir1/dir2/dir3/dir4/file4.txt $ touch dir1/dir2/dir3/dir4/dir5/file5.txt $ tree /tmp/dir1/ /tmp/dir1/ └── dir2 ├── dir3 │ └── dir4 │ ├── dir5 │ │ └── file5.txt │ └── file4.txt └── file2.txt 4 directories, 3 files

3. Using the readlink Command

The readlink command prints canonical file names. We can use the -f option of this command to find the full path of a file:

$ cd /tmp/dir1/dir2/dir3/dir4/dir5/ $ readlink -f file5.txt /tmp/dir1/dir2/dir3/dir4/dir5/file5.txt

4. Using the realpath Command

Alternatively, we can use the realpath command to get the absolute path of a file:

$ cd /tmp/dir1/dir2/dir3/dir4/ $ realpath file4.txt /tmp/dir1/dir2/dir3/dir4/file4.txt

5. Using the Combination of basename and dirname Commands

The basename command is useful when we want to strip the directory and suffix from filenames. Similarly, we can use the dirname command to strip the last component from the file name:

$ basename /tmp/dir1/dir2/dir3/dir4/file4.txt file4.txt $ dirname /tmp/dir1/dir2/dir3/dir4/file4.txt /tmp/dir1/dir2/dir3/dir4

We can use the combination of these two commands to find the full path of a file. Let’s create a simple shell script for the same:

$ cat get_full_path.sh #! /bin/bash echo "$(cd "$(dirname "$1")" && pwd -P)/$(basename "$1")" $ chmod +x get_full_path.sh $ ./get_full_path.sh file4.txt /tmp/dir1/dir2/dir3/dir4/file4.txt

Firstly, we use the dirname command to find the directory in which a file is located. Then we change the directory using the cd command.

Next, we print the current working directory using the pwd command. Here, we have applied the -P option to show the physical location instead of the symbolic link.

Finally, we use the basename command to print the file name without a directory.

6. Using the find Command

The find command searches for files in a directory hierarchy. We can use this command to print the absolute path of a file:

$ cd /tmp/dir1/ $ find $PWD -type f -name file4.txt /tmp/dir1/dir2/dir3/dir4/file4.txt 

7. Conclusion

In this article, we discussed various practical examples to find the absolute path of a file. First, we discussed the usage of the readlink and realpath commands. Then, we used a combination of the basename and dirname commands. Finally, we saw the example of the find command. We can use these commands in day-to-day life to boost our productivity.

Get the Full Path of a File in Linux, Overview · 2. Setup · 3. Using the readlink Command · 4. Using the realpath Command · 5. Using the Combination of basename and dirname Commands.

Get the Path of a Linux Command

1. Overview

A Linux command that we type into a shell can be built-in, a function, an alias, or an external executable. We can find what it is and its path with several Linux utilities such as which , command , type , locate , whatis , and whereis .

In this article, we will explore the which , command , type , and whereis utilities as these are normally found in most Linux-based operating systems.

2. PATH Environment Variable

Before we jump to the explanation of the utilities, we need to know that the application, such as our shell, finds (and executes) the command from a list of directories that are stored in an environment variable called PATH . Each directory is separated with a colon character “:”.

We can show what is inside this variable by calling the echo command:

$ echo $PATH /home/baeldung/.cargo/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games:/snap/bin

This means that when we install a program or application on our system, to be able to call the executable from any directory from our shell, we need to ensure that the PATH variable has the path of the executable .

We can update the PATH variable temporarily by running this command:

$ export PATH=$PATH:/sampledir/path $ echo $PATH /home/baeldung/.cargo/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games:/snap/bin:/sampledir/path 

The PATH will be reset on reboot .

However, we can update the PATH variable permanently by updating the .bashrc file :

export PATH=$PATH:/sampledir/path

3. which Command

Most Linux-based operating systems have the which command installed. We can use this command to get the path of a Linux command:

$ which docker /usr/bin/docker

This shows that when we call the docker command, it will run the Docker executable file in the /usr/bin/ directory.

Moreover, the which command has a parameter -a which will print all matching path names:

$ which -a docker /usr/bin/docker /bin/docker

So we have two executable files in two different directories. The shell uses the one in the /usr/bin/ directory because the directory appears first in the PATH variable, and the file has the right permissions.

Otherwise, it will go to the next executable file in the /bin/ directory:

$ echo $PATH /home/tenzin/.cargo/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games:/snap/bin:/sampledir/path

4. command Command

The command command is another utility that we can use to find the path of a Linux command.

This utility tells us the difference between an executable ( docker ) or an alias ( ls ):

$ command -v docker /usr/bin/docker $ command -V docker docker is hashed (/usr/bin/docker)

We need to pass the -v or -V parameter:

$ command -v ls alias ls='ls --color=auto' $ command -V ls ls is aliased to `ls --color=auto'

Otherwise, it will run the Linux command that we supply :

$ command ls Android Downloads Pictures Templates AndroidStudioProjects file123.txt 'Screenshot from 2021-06-14 16-11-31.png' Videos . 

5. type Command

The type command can not only show the path of a Linux command, but it can also tell if the target is built-in, a function, an alias, or an external executable.

Let’s show the path of a Linux command:

Without the parameter, it will show the command definition:

$ type ls ls is aliased to `ls --color=auto'

If we use the -a parameter, it shows the command definition, executable type, and its path:

$ type -a ls ls is aliased to `ls --color=auto' ls is /usr/bin/ls ls is /bin/ls

We can also use type -t to display the executable type :

$ type -t which file $ type -t command builtin $ type -t type builtin $ type -t whereis file $ type -t ls alias $ type -t docker file 

6. whereis Command

Finally, let’s take a look at the whereis command. This command locates the path of the binary, source, and manual page of a given command.

If we call the utility directly, it shows all the locations of the binary, source, and manual page:

$ whereis docker docker: /usr/bin/docker /etc/docker /usr/libexec/docker /usr/share/man/man1/docker.1.gz

In addition, we can use -b parameter to show just the binary :

$ whereis -b docker docker: /usr/bin/docker /etc/docker /usr/libexec/docker

Moreover, if we want to show just the source (which does not exist on this system):

If we want to show just the manual:

$ whereis -m docker docker: /usr/share/man/man1/docker.1.gz

7. Conclusion

We can use the utilities – which , command , type , and whereis to find the path of a Linux command. Some utilities show more information than others.

As we have seen in this tutorial, there are a few caveats with some utilities, but simply put, we can use these four utilities to get more information about the Linux command we want to use.

Unix shell script find out which directory the script file resides?, 19 Answers 19 · #!/bin/bash # Absolute path to this script, e.g. /home/user/bin/foo.sh SCRIPT=$(readlink -f «$0») # Absolute path this script is in, thus /home/

How to get full path name of a Linux command

As pointed out, which would do it. You could also try:

This will list all the paths that contains progName . I.e whereis -b gcc on my machine returns:

gcc: /usr/bin/gcc /usr/lib/gcc /usr/bin/X11/gcc 

you can use which , it give you path of command:

You can use the which command. In case of a command in your $PATH it will show you the full path:

mureinik@computer ~ $ which cp /usr/bin/cp 

And it will also show details about aliases:

mureinik@computer ~ $ which ls alias ls='ls --color=auto' /usr/bin/ls 

How to extract directory path from file path?, where you get the full path with new_path= $(dirname $) . You change current directory with cd new_path and then run pwd to

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