Basic Linux Commands

Information on this page provides basic commands that you should be familiar with when working within a Linux command line interface (CLI), such as the HPC.

In the examples below, the commands themselves are highlighted in yellow and are followed by the output they produce. Select a topic for details.

ls : list files in a directory

pwd : show full path to current directory

mkdir : make directories

cd : change directory

cp : copy files and directories

rm : remove files

rm -rf : remove a directory and everything in it

man : show usage manual for a command

* ? and other wildcards

~ : shortcut to your home directory

ls : list files in a directory

Simple file listing: [abc123@seldon abc123]$ ls

figure1.fig test.m test.sh

Display extra details (file size, type, date, permissions) with the "long" (-l) option: [abc123@seldon abc123]$ ls -l

total 12 -rw------- 1 abc123 users   1121 Oct 30 16:15 figure1.fig

-rw------- 1 abc123 users     69 Oct 30 16:15 test.m

-rwx------ 1 abc123 users     40 Oct 30 16:10 test.sh

You can use wildcards to select only some of the files. [abc123@seldon abc123]$ ls -l test*

-rw------- 1 abc123 users     69 Oct 30 16:15 test.m -rwx------ 1 abc123 users  40 Oct 30 16:10 test.sh

pwd : show full path to current directory

Print working directory path: [abc123@seldon abc123]$ pwd

/sscc/home/a/abc123

mkdir : make directories

Create a new subdirectory called subdir in the current directory: [abc123@seldon abc123]$ mkdir subdir

[abc123@seldon abc123]$ ls -l total 16

-rw------- 1 abc123 users   1121 Oct 30 16:15 figure1.fig

drwx------ 2 abc123 users   4096 Nov 4 13:55 subdir -rw------- 1 abc123 users  69 Oct 30 16:15 test.m

-rwx------ 1 abc123 users     40 Oct 30 16:10 test.sh

cd : change directory

Switch to a subdirectory called subdir in your current directory: [abc123@seldon abc123]$ cd subdir

[abc123@seldon subdir]$

Two dots .. denote one directory up in your path: [abc123@seldon subdir]$ cd ..

[abc123@seldon abc123]$

To use the full path start with a slash: [abc123@seldon abc123]$ cd /datalib/cps

[abc123@seldon cps]$ pwd /datalib/cps

cp : copy files and directories

Syntax: cp [options]... Source Destination

cp [options]... Source... Directory

Options:

-i : prompt before overwriting files

-r : copy recursively (copy subdirectories and their contents)

-u : overwrite destination files only when the source file is newer

-v : show what is being done

Make a copy of a file called make.do with a different name: [abc123@seldon abc123]$ cp -v make.do make2.do

`make.do' -> `make2.do'

Copy one or more files to another directory: [abc123@seldon abc123]$ cp -v *.do subdir/

`make.do' -> `subdir/make.do' `make2.do' -> `subdir/make2.do'

Copy the contents of a directory and its subdirectories to another place: [abc123@seldon abc123]$ cp -vR subdir/* subdir2/

`subdir/make.do' -> `subdir2/make.do' `subdir/make2.do' -> `subdir2/make2.do'

`subdir/data/file.dat' -> `subdir2/data/file.dat'

rm : remove files

Remove a file called make.do : [abc123@seldon abc123]$ rm make.do

To remove a file with spaces in its name, use quotes: [abc123@seldon abc123]$ rm "file name.txt"

To remove multiple files (or to save time typing long file names) use wildcards. Be careful - wildcards are powerful and could match more files than you intended. Use the ls command first to check what files will be deleted. [abc123@seldon abc123]$ rm *.txt

rm -rf : remove a directory and everything in it

Delete a subdirectory called subdir and all of its contents (including its subdirectories). [abc123@seldon abc123]$ rm -rf subdir

man : show usage manual for a command

Display a more detailed manual for a command:

Press <Space bar> to view the next page

Press q to exit

[ate533@seldon ate533]$ man cp
CP(1)                                 FSF
CP(1)

NAME
cp - copy files and directories

SYNOPSIS
cp [OPTION]... SOURCE DEST
cp [OPTION]... SOURCE... DIRECTORY
cp [OPTION]... --target-directory=DIRECTORY SOURCE...

DESCRIPTION
Copy SOURCE to DEST, or multiple SOURCE(s) to DIRECTORY.
. . .

* ? and other wildcards

You can use these powerful wildcards with any command that takes filenames as an argument. For example prog??.* will match all files with names that start with prog followed by any two characters, a dot, and anything (or nothing) following the dot.

~ : shortcut to your home directory

You can reference your home directory in your commands and programs with the character tilde ~ shortcut. If your home directory is

/sscc/home/a/abc123

then instead of writing out the full path to the file

/sscc/home/a/abc123/data/input.dat

you can just write

~/data/input.dat

Further Information

The software installed upon our HPC runs under the Linux/Unix operating system.

• Linux guide for beginners

Tutorials are shared under a Creative Commons License.