Basic Linux Commands

Here are some basic commands that you need to work on the cluster. In these examples the commands themselves are highlighted in yellow and are followed by the output they produce.

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

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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

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pwd : show full path to current directory

Print working directory path:

[abc123@seldon abc123]$ pwd
/sscc/home/a/abc123

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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

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cd : change 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

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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'

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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

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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

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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.

                                     . . .

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* ? 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.

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~ : 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

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

~/data/input.dat