Linux command cheat sheet

Linux Cheat Sheet

Getting Around in the File System
pwd
Path of working directory - tells you what directory you are in

ls
List - Lists the files in the current directory

ls -l
Lists the files and their attributes

cd
change directory - Change to the directory specified

Dealing with Files

cp
copy - Make a copy of a file

cp -R
Make a copy of a directory

mv
move - Move or rename a file

rm
remove - Delete a file

more
Page through a file.

grep
Search a file for a keyword

vi
Edit a file. (See Ruling WebGUI's vi Cheat sheet for details>

chmod
change mode - Change the mode or permissions on a file.
Mode = ogw or owner, group, world permissions. example: 755
0=nothing
4=read
5=read / execute
6=read / write
7=read / write / execute

chown
change owner - Change the owner of a file

Dealing with Environment Variables

export =
Set and environment variable in teh current shell.

set
Show all of the current envireonment variables that have been exported

unset
Delete an environment variable

Power Users

df -k
Determine how full the partitions on the local hard disks are.

du -ks
Determine the disk usage of a given directory and all sub directories

find -name
Locate a file on the file system.

ps -ef
Get a look at the processes running on the machine

top
Take a look at the memory and CPU usage as well as the top processes on the machine

man
Get help for a given command

diff
Report the differences between two files.

gzip
Compress a file.

gunzip
Decompress a file.

tail
Look at the end of a file.

tar cf ./*
Tar all the files in this directory into a tar-ball in the lower directory

tar xvf
De-tar the contents of a tar-ball

Perl Specific

perl -w
Execute a Perl Script with warnings.

perl -c
Get compilation errors for a Perl script

perldoc ::
Get help for a Perl function in a given module.

perldoc perlfunc
Get help on basic Perl functions.

perldoc perlpod
Get help on Perl (POD = Plain Old Documentation) documentation

Java Specific

java
Run a compiled class

java -client
Run a compiled class where the JVM is optimized as a client

java -server
Run compiled class where the JVM is optimized as a server

javac
Compile a source file