apropos: Search the whatis database for files containing specific strings.
bdflush: Kernel daemon that saves dirty buffers in memory to the disk.
cd: Change the current directory. With no arguments "cd" changes to the users home directory.
chmod: chmod <specification> <filename> - Effect: Change the file permissions.
chown: chown <owner1> <filename> Effect: Change ownership of a file to owner1.
chgrp: chgrp <group1> <filename> Effect: Change group.
cksum: Perform a checksum and count bytes in a file.
cp: cp <source> <destination> Copy a file from one location to another.
dd: Convert and copy a file formatting according to the options. Disk or data duplication.
dir: List directory contents.
dircolors: Set colors up for ls.
file: Determines file type. Also can tell type of library (a.out or ELF).
find: Ex: find $Home –name readme Print search for readme starting at home and output full path.
install: Copy multiple files and set attributes.
ln: Make links between files.
locate: File locating program that uses the slocate database.
losetup: Loopback device setup.
ls: List files. Option -a, lists all.
mkdir: Make a directory.
mknod: Make a block or character special file.
mktemp: Make temporary filename.
mv: Move or rename a file. Syntax: mv <source> <destination> Ex: mv filename directoryname/newfilename
pathchk: Check whether filenames are valid or portable.
pwd: Print or list the working directory with full path (present working directory).
rm: Ex: "rm .*" - Effect: Delete system files (Remove files) –i is interactive option.
rmdir: rmdir <directory> - Remove a directory. The directory must be empty.
slocate: Provides a secure way to index files and search for them. It builds a database of files on the system.
stat(1u): Used to print out inode information on a file.
sum: Checksum and count the blocks in a file.
test: Check file types and compare values.
touch: Change file timestamps to the current time. Make the file if it doesn't exist.
update: Kernel daemon to flush dirty buffers back to disk.
vdir: List directory contents.
whatis: Search the whatis database for complete words.
wheris: Locate the binary, source and man page files for a command.
which: Show full path of commands where given commands reside.
File viewing and editing Commands
ed: Editor
emacs: Full screen editor.
gitview: A hexadecimal or ASC file viewer.
head: head linuxdoc.txt - Look at the first 10 lines of linuxdoc.txt.
jed: Editor
joe: Editor
less: q-mandatory to exit, Used to view files.
more: b-back q-quit h-help, Used to view files.
pico: Simple text editor.
tail: tail linuxdoc.txt - Look at the last 10 lines of linuxdoc.txt.
vi: Editor with a command mode and text mode. Starts in command mode.
File Compression, Backing up and Restoring Commands
ar: Create modify and extract from archives.
bunzip2: File decompression program.
bzcat: Decompress files to stdout.
bzip2: File compression program.
bzip2recover: Recovers data from damaged bzip2 files.
compress: Compress data.
dump: Reads the filesystem directly.
gunzip: unzip <file> - unzip a gz file.
gzexe: Compress executable files in place.
gzip: gzip <file> - zip a file to a gz file.
uncompress: Expand data.
unzip: unzip <file> - unzip a zip file. Files ending in ".gz" or ".zip" are compressed.
zcat: Used to restore compressed files.
zcmp: Compare compressed files.
zdiff: Compare compressed files.
zforce: Force a .gz extension on all gzip files.
zgrep: Search possibly compressed files for a regular expression.
zmore: File filter for crt viewing of compressed text.
znew: Recompress .z files to .gz files.
zip: zip <file> - make a zip file.
Unix/Linux Printing Commands
banner: Print a large banner on printer.
lpr: Print, submits a job to the printer.
Ex: lpr -Pdest filename.
lpc: Lets you check the status of the printer and set its state.
lpq: Shows the contents of a spool directory for a given printer.
lprm: Removes a job from the printer queue.
gs: Ghostscript - A PostScript interpreter.
pr: Print a file. Ex: pr filename |pg.
tunelp: Set various parameters for the lp device.