hanjoong@ubuntu:~$ pwd
/home/hanjoong
hanjoong@ubuntu:~$

Usage: ls [OPTION]... [FILE]...
List information about the FILEs (the current directory by default).
Sort entries alphabetically if none of -cftuvSUX nor --sort is specified.

Mandatory arguments to long options are mandatory for short options too.
  -a, --all                  do not ignore entries starting with .
  -A, --almost-all           do not list implied . and ..
      --author               with -l, print the author of each file
  -b, --escape               print C-style escapes for nongraphic characters
      --block-size=SIZE      scale sizes by SIZE before printing them.  E.g.,
                               '--block-size=M' prints sizes in units of
                               1,048,576 bytes.  See SIZE format below.
  -B, --ignore-backups       do not list implied entries ending with ~
  -c                         with -lt: sort by, and show, ctime (time of last
                               modification of file status information)
                               with -l: show ctime and sort by name
                               otherwise: sort by ctime, newest first
  -C                         list entries by columns
      --color[=WHEN]         colorize the output.  WHEN defaults to 'always'
                               or can be 'never' or 'auto'.  More info below
  -d, --directory            list directory entries instead of contents,
                               and do not dereference symbolic links
  -D, --dired                generate output designed for Emacs' dired mode
  -f                         do not sort, enable -aU, disable -ls --color
  -F, --classify             append indicator (one of */=>@|) to entries
      --file-type            likewise, except do not append '*'
      --format=WORD          across -x, commas -m, horizontal -x, long -l,
                               single-column -1, verbose -l, vertical -C
      --full-time            like -l --time-style=full-iso
  -g                         like -l, but do not list owner
      --group-directories-first
                             group directories before files.
                               augment with a --sort option, but any
                               use of --sort=none (-U) disables grouping
  -G, --no-group             in a long listing, don't print group names
  -h, --human-readable       with -l, print sizes in human readable format
                               (e.g., 1K 234M 2G)
      --si                   likewise, but use powers of 1000 not 1024
  -H, --dereference-command-line
                             follow symbolic links listed on the command line
      --dereference-command-line-symlink-to-dir
                             follow each command line symbolic link
                             that points to a directory
      --hide=PATTERN         do not list implied entries matching shell PATTERN
                               (overridden by -a or -A)
      --indicator-style=WORD  append indicator with style WORD to entry names:
                               none (default), slash (-p),
                               file-type (--file-type), classify (-F)
  -i, --inode                print the index number of each file
  -I, --ignore=PATTERN       do not list implied entries matching shell PATTERN
  -k, --kibibytes            use 1024-byte blocks
  -l                         use a long listing format
  -L, --dereference          when showing file information for a symbolic
                               link, show information for the file the link
                               references rather than for the link itself
  -m                         fill width with a comma separated list of entries
  -n, --numeric-uid-gid      like -l, but list numeric user and group IDs
  -N, --literal              print raw entry names (don't treat e.g. control
                               characters specially)
  -o                         like -l, but do not list group information
  -p, --indicator-style=slash
                             append / indicator to directories
  -q, --hide-control-chars   print ? instead of non graphic characters
      --show-control-chars   show non graphic characters as-is (default
                             unless program is 'ls' and output is a terminal)
  -Q, --quote-name           enclose entry names in double quotes
      --quoting-style=WORD   use quoting style WORD for entry names:
                               literal, locale, shell, shell-always, c, escape
  -r, --reverse              reverse order while sorting
  -R, --recursive            list subdirectories recursively
  -s, --size                 print the allocated size of each file, in blocks
  -S                         sort by file size
      --sort=WORD            sort by WORD instead of name: none -U,
                             extension -X, size -S, time -t, version -v
      --time=WORD            with -l, show time as WORD instead of modification
                             time: atime -u, access -u, use -u, ctime -c,
                             or status -c; use specified time as sort key
                             if --sort=time
      --time-style=STYLE     with -l, show times using style STYLE:
                             full-iso, long-iso, iso, locale, +FORMAT.
                             FORMAT is interpreted like 'date'; if FORMAT is
                             FORMAT1<newline>FORMAT2, FORMAT1 applies to
                             non-recent files and FORMAT2 to recent files;
                             if STYLE is prefixed with 'posix-', STYLE
                             takes effect only outside the POSIX locale
  -t                         sort by modification time, newest first
  -T, --tabsize=COLS         assume tab stops at each COLS instead of 8
  -u                         with -lt: sort by, and show, access time
                               with -l: show access time and sort by name
                               otherwise: sort by access time
  -U                         do not sort; list entries in directory order
  -v                         natural sort of (version) numbers within text
  -w, --width=COLS           assume screen width instead of current value
  -x                         list entries by lines instead of by columns
  -X                         sort alphabetically by entry extension
  -Z, --context              print any SELinux security context of each file
  -1                         list one file per line
      --help     display this help and exit
      --version  output version information and exit

SIZE is an integer and optional unit (example: 10M is 10*1024*1024).  Units
are K, M, G, T, P, E, Z, Y (powers of 1024) or KB, MB, ... (powers of 1000).

Using color to distinguish file types is disabled both by default and
with --color=never.  With --color=auto, ls emits color codes only when
standard output is connected to a terminal.  The LS_COLORS environment
variable can change the settings.  Use the dircolors command to set it.

hanjoong@ubuntu:~/apache-activemq-5.14.3$ ls -lat
total 15916
drwxr-xr-x  6 hanjoong hanjoong     4096 Jan 25 01:05 ..
drwxr-xr-x 10 root     root         4096 Dec 19 07:41 .
drwxr-xr-x  7 root     root         4096 Dec 19 07:41 examples
-rw-r--r--  1 root     root        40580 Dec 19 07:41 LICENSE
-rw-r--r--  1 root     root         3334 Dec 19 07:41 NOTICE
-rw-r--r--  1 root     root         2610 Dec 19 07:41 README.txt
-rwxr-xr-x  1 root     root     16207404 Dec 19 07:39 activemq-all-5.14.3.jar
drwxr-xr-x  3 root     root         4096 May  5  2016 data
drwxr-xr-x  6 root     root         4096 May  5  2016 lib
drwxr-xr-x  5 root     root         4096 May  5  2016 bin
drwxr-xr-x  3 root     root         4096 May  5  2016 webapps-demo
drwxr-xr-x  2 root     root         4096 May  5  2016 conf
drwxr-xr-x  6 root     root         4096 May  5  2016 webapps
drwxr-xr-x  2 root     root         4096 May  5  2016 docs
hanjoong@ubuntu:~/apache-activemq-5.14.3$

hanjoong@ubuntu:/home/activemq$ pwd
/home/activemq
hanjoong@ubuntu:/home/activemq$ cd ~
hanjoong@ubuntu:~$ pwd
/home/hanjoong
hanjoong@ubuntu:~$ cd .
hanjoong@ubuntu:~$ cd ..
hanjoong@ubuntu:/home$ cd -
/home/hanjoong
hanjoong@ubuntu:~$ pwd
/home/hanjoong
hanjoong@ubuntu:~$ cd -
/home
hanjoong@ubuntu:/home$ pwd
/home
hanjoong@ubuntu:/home$

Usage: cat [OPTION]... [FILE]...
Concatenate FILE(s), or standard input, to standard output.

  -A, --show-all           equivalent to -vET
  -b, --number-nonblank    number nonempty output lines, overrides -n
  -e                       equivalent to -vE
  -E, --show-ends          display $ at end of each line
  -n, --number             number all output lines
  -s, --squeeze-blank      suppress repeated empty output lines
  -t                       equivalent to -vT
  -T, --show-tabs          display TAB characters as ^I
  -u                       (ignored)
  -v, --show-nonprinting   use ^ and M- notation, except for LFD and TAB
      --help     display this help and exit
      --version  output version information and exit

With no FILE, or when FILE is -, read standard input.

Examples:
  cat f - g  Output f's contents, then standard input, then g's contents.
  cat        Copy standard input to standard output.

hanjoong@ubuntu:~$ cat -n .profile
     1  # ~/.profile: executed by the command interpreter for login shells.
     2  # This file is not read by bash(1), if ~/.bash_profile or ~/.bash_login
     3  # exists.
     4  # see /usr/share/doc/bash/examples/startup-files for examples.
     5  # the files are located in the bash-doc package.
     6
     7  # the default umask is set in /etc/profile; for setting the umask
     8  # for ssh logins, install and configure the libpam-umask package.
     9  #umask 022
    10
    11  # if running bash
    12  if [ -n "$BASH_VERSION" ]; then
    13      # include .bashrc if it exists
    14      if [ -f "$HOME/.bashrc" ]; then
    15          . "$HOME/.bashrc"
    16      fi
    17  fi
    18
    19  # set PATH so it includes user's private bin if it exists
    20  if [ -d "$HOME/bin" ] ; then
    21      PATH="$HOME/bin:$PATH"
    22  fi

Mandatory arguments to long options are mandatory for short options too.
  -a, --archive                same as -dR --preserve=all
      --attributes-only        don't copy the file data, just the attributes
      --backup[=CONTROL]       make a backup of each existing destination file
  -b                           like --backup but does not accept an argument
      --copy-contents          copy contents of special files when recursive
  -d                           same as --no-dereference --preserve=links
  -f, --force                  if an existing destination file cannot be
                                 opened, remove it and try again (this option
                                 is ignored when the -n option is also used)
  -i, --interactive            prompt before overwrite (overrides a previous -n
                                  option)
  -H                           follow command-line symbolic links in SOURCE
  -l, --link                   hard link files instead of copying
  -L, --dereference            always follow symbolic links in SOURCE
  -n, --no-clobber             do not overwrite an existing file (overrides
                                 a previous -i option)
  -P, --no-dereference         never follow symbolic links in SOURCE
  -p                           same as --preserve=mode,ownership,timestamps
      --preserve[=ATTR_LIST]   preserve the specified attributes (default:
                                 mode,ownership,timestamps), if possible
                                 additional attributes: context, links, xattr,
                                 all
      --no-preserve=ATTR_LIST  don't preserve the specified attributes
      --parents                use full source file name under DIRECTORY
  -R, -r, --recursive          copy directories recursively
      --reflink[=WHEN]         control clone/CoW copies. See below
      --remove-destination     remove each existing destination file before
                                 attempting to open it (contrast with --force)
      --sparse=WHEN            control creation of sparse files. See below
      --strip-trailing-slashes  remove any trailing slashes from each SOURCE
                                 argument
  -s, --symbolic-link          make symbolic links instead of copying
  -S, --suffix=SUFFIX          override the usual backup suffix
  -t, --target-directory=DIRECTORY  copy all SOURCE arguments into DIRECTORY
  -T, --no-target-directory    treat DEST as a normal file
  -u, --update                 copy only when the SOURCE file is newer
                                 than the destination file or when the
                                 destination file is missing
  -v, --verbose                explain what is being done
  -x, --one-file-system        stay on this file system
      --help     display this help and exit
      --version  output version information and exit

hanjoong@ubuntu:~/apache-activemq-5.14.3$ cp -b activemq-all-5.14.3.jar test.jar
hanjoong@ubuntu:~/apache-activemq-5.14.3$ ls -la
total 47572
drwxrwxrwx 10 root     root         4096 Feb 26 10:40 .
drwxr-xr-x  6 hanjoong hanjoong     4096 Jan 25 01:05 ..
-rwxrwxrwx  1 root     root     16207404 Dec 19 07:39 activemq-all-5.14.3.jar
drwxr-xr-x  5 root     root         4096 May  5  2016 bin
drwxr-xr-x  2 root     root         4096 May  5  2016 conf
drwxr-xr-x  3 root     root         4096 May  5  2016 data
drwxr-xr-x  2 root     root         4096 May  5  2016 docs
drwxr-xr-x  7 root     root         4096 Dec 19 07:41 examples
drwxr-xr-x  6 root     root         4096 May  5  2016 lib
-rw-r--r--  1 root     root        40580 Dec 19 07:41 LICENSE
-rw-r--r--  1 root     root         3334 Dec 19 07:41 NOTICE
-rw-r--r--  1 root     root         2610 Dec 19 07:41 README.txt
-rwxrwxr-x  1 hanjoong hanjoong 16207404 Feb 26 10:40 test.jar
-rwxrwxr-x  1 hanjoong hanjoong 16207404 Feb 26 10:40 test.jar~
drwxr-xr-x  6 root     root         4096 May  5  2016 webapps
drwxr-xr-x  3 root     root         4096 May  5  2016 webapps-demo
hanjoong@ubuntu:~/apache-activemq-5.14.3$

Usage: mv [OPTION]... [-T] SOURCE DEST
  or:  mv [OPTION]... SOURCE... DIRECTORY
  or:  mv [OPTION]... -t DIRECTORY SOURCE...
Rename SOURCE to DEST, or move SOURCE(s) to DIRECTORY.

Mandatory arguments to long options are mandatory for short options too.
      --backup[=CONTROL]       make a backup of each existing destination file
  -b                           like --backup but does not accept an argument
  -f, --force                  do not prompt before overwriting
  -i, --interactive            prompt before overwrite
  -n, --no-clobber             do not overwrite an existing file
If you specify more than one of -i, -f, -n, only the final one takes effect.
      --strip-trailing-slashes  remove any trailing slashes from each SOURCE
                                 argument
  -S, --suffix=SUFFIX          override the usual backup suffix
  -t, --target-directory=DIRECTORY  move all SOURCE arguments into DIRECTORY
  -T, --no-target-directory    treat DEST as a normal file
  -u, --update                 move only when the SOURCE file is newer
                                 than the destination file or when the
                                 destination file is missing
  -v, --verbose                explain what is being done
      --help     display this help and exit
      --version  output version information and exit

The backup suffix is '~', unless set with --suffix or SIMPLE_BACKUP_SUFFIX.
The version control method may be selected via the --backup option or through
the VERSION_CONTROL environment variable.  Here are the values:

  none, off       never make backups (even if --backup is given)
  numbered, t     make numbered backups
  existing, nil   numbered if numbered backups exist, simple otherwise
  simple, never   always make simple backups

Remove (unlink) the FILE(s).

  -f, --force           ignore nonexistent files and arguments, never prompt
  -i                    prompt before every removal
  -I                    prompt once before removing more than three files, or
                          when removing recursively.  Less intrusive than -i,
                          while still giving protection against most mistakes
      --interactive[=WHEN]  prompt according to WHEN: never, once (-I), or
                          always (-i).  Without WHEN, prompt always
      --one-file-system  when removing a hierarchy recursively, skip any
                          directory that is on a file system different from
                          that of the corresponding command line argument
      --no-preserve-root  do not treat '/' specially
      --preserve-root   do not remove '/' (default)
  -r, -R, --recursive   remove directories and their contents recursively
  -d, --dir             remove empty directories
  -v, --verbose         explain what is being done
      --help     display this help and exit
      --version  output version information and exit

By default, rm does not remove directories.  Use the --recursive (-r or -R)
option to remove each listed directory, too, along with all of its contents.

To remove a file whose name starts with a '-', for example '-foo',
use one of these commands:
  rm -- -foo

  rm ./-foo

Usage: chmod [OPTION]... MODE[,MODE]... FILE...
  or:  chmod [OPTION]... OCTAL-MODE FILE...
  or:  chmod [OPTION]... --reference=RFILE FILE...
Change the mode of each FILE to MODE.
With --reference, change the mode of each FILE to that of RFILE.

  -c, --changes          like verbose but report only when a change is made
  -f, --silent, --quiet  suppress most error messages
  -v, --verbose          output a diagnostic for every file processed
      --no-preserve-root  do not treat '/' specially (the default)
      --preserve-root    fail to operate recursively on '/'
      --reference=RFILE  use RFILE's mode instead of MODE values
  -R, --recursive        change files and directories recursively
      --help     display this help and exit
      --version  output version information and exit

Each MODE is of the form '[ugoa]*([-+=]([rwxXst]*|[ugo]))+|[-+=][0-7]+'.

hanjoong@ubuntu:~/test$ ls -la
total 12
drwxrwxr-x 2 hanjoong hanjoong 4096 Feb 26 10:49 .
drwxr-xr-x 7 hanjoong hanjoong 4096 Feb 26 10:48 ..
-rw-rw-rw- 1 hanjoong hanjoong    6 Feb 26 10:49 test.txt
hanjoong@ubuntu:~/test$ chmod o-r,o-w *
hanjoong@ubuntu:~/test$ ls -la
total 12
drwxrwxr-x 2 hanjoong hanjoong 4096 Feb 26 10:49 .
drwxr-xr-x 7 hanjoong hanjoong 4096 Feb 26 10:48 ..
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:49 test.txt
hanjoong@ubuntu:~/test$

Compress or uncompress FILEs (by default, compress FILES in-place).

Mandatory arguments to long options are mandatory for short options too.

  -c, --stdout      write on standard output, keep original files unchanged
  -d, --decompress  decompress
  -f, --force       force overwrite of output file and compress links
  -h, --help        give this help
  -k, --keep        keep (don't delete) input files
  -l, --list        list compressed file contents
  -L, --license     display software license
  -n, --no-name     do not save or restore the original name and time stamp
  -N, --name        save or restore the original name and time stamp
  -q, --quiet       suppress all warnings
  -r, --recursive   operate recursively on directories
  -S, --suffix=SUF  use suffix SUF on compressed files
  -t, --test        test compressed file integrity
  -v, --verbose     verbose mode
  -V, --version     display version number
  -1, --fast        compress faster
  -9, --best        compress better
  --rsyncable       Make rsync-friendly archive

With no FILE, or when FILE is -, read standard input.

hanjoong@ubuntu:~/test$ ls -la
total 32
drwxrwxr-x 2 hanjoong hanjoong 4096 Feb 26 11:04 .
drwxr-xr-x 7 hanjoong hanjoong 4096 Feb 26 10:48 ..
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:57 data01
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:57 data02
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:57 data03
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:57 data04
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:57 data05
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:49 test.txt
hanjoong@ubuntu:~/test$ gzip data01
hanjoong@ubuntu:~/test$ ls -la
total 32
drwxrwxr-x 2 hanjoong hanjoong 4096 Feb 26 11:08 .
drwxr-xr-x 7 hanjoong hanjoong 4096 Feb 26 10:48 ..
-rw-rw---- 1 hanjoong hanjoong   33 Feb 26 10:57 data01.gz
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:57 data02
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:57 data03
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:57 data04
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:57 data05
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:49 test.txt
hanjoong@ubuntu:~/test$ gzip -d data01.gz
hanjoong@ubuntu:~/test$ ls -la
total 32
drwxrwxr-x 2 hanjoong hanjoong 4096 Feb 26 11:08 .
drwxr-xr-x 7 hanjoong hanjoong 4096 Feb 26 10:48 ..
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:57 data01
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:57 data02
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:57 data03
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:57 data04
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:57 data05
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:49 test.txt
hanjoong@ubuntu:~/test$

Usage: tar [OPTION...] [FILE]...
GNU 'tar' saves many files together into a single tape or disk archive, and can
restore individual files from the archive.

Examples:
  tar -cf archive.tar foo bar  # Create archive.tar from files foo and bar.
  tar -tvf archive.tar         # List all files in archive.tar verbosely.
  tar -xf archive.tar          # Extract all files from archive.tar.

 Main operation mode:

  -A, --catenate, --concatenate   append tar files to an archive
  -c, --create               create a new archive
  -d, --diff, --compare      find differences between archive and file system
      --delete               delete from the archive (not on mag tapes!)
  -r, --append               append files to the end of an archive
  -t, --list                 list the contents of an archive
      --test-label           test the archive volume label and exit
  -u, --update               only append files newer than copy in archive
  -x, --extract, --get       extract files from an archive

 Operation modifiers:

      --check-device         check device numbers when creating incremental
                             archives (default)
  -g, --listed-incremental=FILE   handle new GNU-format incremental backup
  -G, --incremental          handle old GNU-format incremental backup
      --ignore-failed-read   do not exit with nonzero on unreadable files
      --level=NUMBER         dump level for created listed-incremental archive
  -n, --seek                 archive is seekable
      --no-check-device      do not check device numbers when creating
                             incremental archives
      --no-seek              archive is not seekable
      --occurrence[=NUMBER]  process only the NUMBERth occurrence of each file
                             in the archive; this option is valid only in
                             conjunction with one of the subcommands --delete,
                             --diff, --extract or --list and when a list of
                             files is given either on the command line or via
                             the -T option; NUMBER defaults to 1
      --sparse-version=MAJOR[.MINOR]
                             set version of the sparse format to use (implies
                             --sparse)
  -S, --sparse               handle sparse files efficiently

 Overwrite control:

  -k, --keep-old-files       don't replace existing files when extracting,
                             treat them as errors
      --keep-directory-symlink   preserve existing symlinks to directories when
                             extracting
      --keep-newer-files     don't replace existing files that are newer than
                             their archive copies
      --no-overwrite-dir     preserve metadata of existing directories
      --overwrite            overwrite existing files when extracting
      --overwrite-dir        overwrite metadata of existing directories when
                             extracting (default)
      --recursive-unlink     empty hierarchies prior to extracting directory
      --remove-files         remove files after adding them to the archive
      --skip-old-files       don't replace existing files when extracting,
                             silently skip over them
  -U, --unlink-first         remove each file prior to extracting over it
  -W, --verify               attempt to verify the archive after writing it

 Select output stream:

      --ignore-command-error ignore exit codes of children
      --no-ignore-command-error   treat non-zero exit codes of children as
                             error
  -O, --to-stdout            extract files to standard output
      --to-command=COMMAND   pipe extracted files to another program

 Handling of file attributes:

      --atime-preserve[=METHOD]   preserve access times on dumped files, either
                             by restoring the times after reading
                             (METHOD='replace'; default) or by not setting the
                             times in the first place (METHOD='system')
      --delay-directory-restore   delay setting modification times and
                             permissions of extracted directories until the end
                             of extraction
      --group=NAME           force NAME as group for added files
      --mode=CHANGES         force (symbolic) mode CHANGES for added files
      --mtime=DATE-OR-FILE   set mtime for added files from DATE-OR-FILE
  -m, --touch                don't extract file modified time
      --no-delay-directory-restore
                             cancel the effect of --delay-directory-restore
                             option
      --no-same-owner        extract files as yourself (default for ordinary
                             users)
      --no-same-permissions  apply the user's umask when extracting permissions
                             from the archive (default for ordinary users)
      --numeric-owner        always use numbers for user/group names
      --owner=NAME           force NAME as owner for added files
  -p, --preserve-permissions, --same-permissions
                             extract information about file permissions
                             (default for superuser)
      --preserve             same as both -p and -s
      --same-owner           try extracting files with the same ownership as
                             exists in the archive (default for superuser)
  -s, --preserve-order, --same-order
                             member arguments are listed in the same order as
                             the files in the archive

 Handling of extended file attributes:

      --acls                 Enable the POSIX ACLs support
      --no-acls              Disable the POSIX ACLs support
      --no-selinux           Disable the SELinux context support
      --no-xattrs            Disable extended attributes support
      --selinux              Enable the SELinux context support
      --xattrs               Enable extended attributes support
      --xattrs-exclude=MASK  specify the exclude pattern for xattr keys
      --xattrs-include=MASK  specify the include pattern for xattr keys

 Device selection and switching:

  -f, --file=ARCHIVE         use archive file or device ARCHIVE
      --force-local          archive file is local even if it has a colon
  -F, --info-script=NAME, --new-volume-script=NAME
                             run script at end of each tape (implies -M)
  -L, --tape-length=NUMBER   change tape after writing NUMBER x 1024 bytes
  -M, --multi-volume         create/list/extract multi-volume archive
      --rmt-command=COMMAND  use given rmt COMMAND instead of rmt
      --rsh-command=COMMAND  use remote COMMAND instead of rsh
      --volno-file=FILE      use/update the volume number in FILE

 Device blocking:

  -b, --blocking-factor=BLOCKS   BLOCKS x 512 bytes per record
  -B, --read-full-records    reblock as we read (for 4.2BSD pipes)
  -i, --ignore-zeros         ignore zeroed blocks in archive (means EOF)
      --record-size=NUMBER   NUMBER of bytes per record, multiple of 512

 Archive format selection:

  -H, --format=FORMAT        create archive of the given format

 FORMAT is one of the following:

    gnu                      GNU tar 1.13.x format
    oldgnu                   GNU format as per tar <= 1.12
    pax                      POSIX 1003.1-2001 (pax) format
    posix                    same as pax
    ustar                    POSIX 1003.1-1988 (ustar) format
    v7                       old V7 tar format

      --old-archive, --portability
                             same as --format=v7
      --pax-option=keyword[[:]=value][,keyword[[:]=value]]...
                             control pax keywords
      --posix                same as --format=posix
  -V, --label=TEXT           create archive with volume name TEXT; at
                             list/extract time, use TEXT as a globbing pattern
                             for volume name

 Compression options:

  -a, --auto-compress        use archive suffix to determine the compression
                             program
  -I, --use-compress-program=PROG
                             filter through PROG (must accept -d)
  -j, --bzip2                filter the archive through bzip2
  -J, --xz                   filter the archive through xz
      --lzip                 filter the archive through lzip
      --lzma                 filter the archive through xz
      --lzop
      --no-auto-compress     do not use archive suffix to determine the
                             compression program
  -z, --gzip, --gunzip, --ungzip   filter the archive through gzip
  -Z, --compress, --uncompress   filter the archive through compress

 Local file selection:

      --add-file=FILE        add given FILE to the archive (useful if its name
                             starts with a dash)
      --backup[=CONTROL]     backup before removal, choose version CONTROL
  -C, --directory=DIR        change to directory DIR
      --exclude=PATTERN      exclude files, given as a PATTERN
      --exclude-backups      exclude backup and lock files
      --exclude-caches       exclude contents of directories containing
                             CACHEDIR.TAG, except for the tag file itself
      --exclude-caches-all   exclude directories containing CACHEDIR.TAG
      --exclude-caches-under exclude everything under directories containing
                             CACHEDIR.TAG
      --exclude-tag=FILE     exclude contents of directories containing FILE,
                             except for FILE itself
      --exclude-tag-all=FILE exclude directories containing FILE
      --exclude-tag-under=FILE   exclude everything under directories
                             containing FILE
      --exclude-vcs          exclude version control system directories
  -h, --dereference          follow symlinks; archive and dump the files they
                             point to
      --hard-dereference     follow hard links; archive and dump the files they
                             refer to
  -K, --starting-file=MEMBER-NAME
                             begin at member MEMBER-NAME when reading the
                             archive
      --newer-mtime=DATE     compare date and time when data changed only
      --no-null              disable the effect of the previous --null option
      --no-recursion         avoid descending automatically in directories
      --no-unquote           do not unquote filenames read with -T
      --null                 -T reads null-terminated names, disable -C
  -N, --newer=DATE-OR-FILE, --after-date=DATE-OR-FILE
                             only store files newer than DATE-OR-FILE
      --one-file-system      stay in local file system when creating archive
  -P, --absolute-names       don't strip leading '/'s from file names
      --recursion            recurse into directories (default)
      --suffix=STRING        backup before removal, override usual suffix ('~'
                             unless overridden by environment variable
                             SIMPLE_BACKUP_SUFFIX)
  -T, --files-from=FILE      get names to extract or create from FILE
      --unquote              unquote filenames read with -T (default)
  -X, --exclude-from=FILE    exclude patterns listed in FILE

 File name transformations:

      --strip-components=NUMBER   strip NUMBER leading components from file
                             names on extraction
      --transform=EXPRESSION, --xform=EXPRESSION
                             use sed replace EXPRESSION to transform file
                             names

 File name matching options (affect both exclude and include patterns):

      --anchored             patterns match file name start
      --ignore-case          ignore case
      --no-anchored          patterns match after any '/' (default for
                             exclusion)
      --no-ignore-case       case sensitive matching (default)
      --no-wildcards         verbatim string matching
      --no-wildcards-match-slash   wildcards do not match '/'
      --wildcards            use wildcards (default for exclusion)
      --wildcards-match-slash   wildcards match '/' (default for exclusion)

 Informative output:

      --checkpoint[=NUMBER]  display progress messages every NUMBERth record
                             (default 10)
      --checkpoint-action=ACTION   execute ACTION on each checkpoint
      --full-time            print file time to its full resolution
      --index-file=FILE      send verbose output to FILE
  -l, --check-links          print a message if not all links are dumped
      --no-quote-chars=STRING   disable quoting for characters from STRING
      --quote-chars=STRING   additionally quote characters from STRING
      --quoting-style=STYLE  set name quoting style; see below for valid STYLE
                             values
  -R, --block-number         show block number within archive with each message

      --show-defaults        show tar defaults
      --show-omitted-dirs    when listing or extracting, list each directory
                             that does not match search criteria
      --show-snapshot-field-ranges
                             show valid ranges for snapshot-file fields
      --show-transformed-names, --show-stored-names
                             show file or archive names after transformation
      --totals[=SIGNAL]      print total bytes after processing the archive;
                             with an argument - print total bytes when this
                             SIGNAL is delivered; Allowed signals are: SIGHUP,
                             SIGQUIT, SIGINT, SIGUSR1 and SIGUSR2; the names
                             without SIG prefix are also accepted
      --utc                  print file modification times in UTC
  -v, --verbose              verbosely list files processed
      --warning=KEYWORD      warning control
  -w, --interactive, --confirmation
                             ask for confirmation for every action

 Compatibility options:

  -o                         when creating, same as --old-archive; when
                             extracting, same as --no-same-owner

 Other options:

  -?, --help                 give this help list
      --restrict             disable use of some potentially harmful options
      --usage                give a short usage message
      --version              print program version

Mandatory or optional arguments to long options are also mandatory or optional
for any corresponding short options.

The backup suffix is '~', unless set with --suffix or SIMPLE_BACKUP_SUFFIX.
The version control may be set with --backup or VERSION_CONTROL, values are:

  none, off       never make backups
  t, numbered     make numbered backups
  nil, existing   numbered if numbered backups exist, simple otherwise
  never, simple   always make simple backups

Valid arguments for the --quoting-style option are:

  literal
  shell
  shell-always
  c
  c-maybe
  escape
  locale
  clocale

*This* tar defaults to:
--format=gnu -f- -b20 --quoting-style=escape --rmt-command=/usr/lib/tar/rmt
--rsh-command=/usr/bin/rsh

hanjoong@ubuntu:~/test$ ls -la
total 16
drwxrwxr-x 3 hanjoong hanjoong 4096 Feb 26 11:26 .
drwxr-xr-x 7 hanjoong hanjoong 4096 Feb 26 10:48 ..
drwxrwxr-x 2 hanjoong hanjoong 4096 Feb 26 11:13 pack
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:49 test.txt
hanjoong@ubuntu:~/test$ tar -cvf pack.tar pack
pack/
pack/data05
pack/data03
pack/data02
pack/data01
pack/data04
hanjoong@ubuntu:~/test$ ls -la
total 28
drwxrwxr-x 3 hanjoong hanjoong  4096 Feb 26 11:27 .
drwxr-xr-x 7 hanjoong hanjoong  4096 Feb 26 10:48 ..
drwxrwxr-x 2 hanjoong hanjoong  4096 Feb 26 11:13 pack
-rw-rw-r-- 1 hanjoong hanjoong 10240 Feb 26 11:27 pack.tar
-rw-rw---- 1 hanjoong hanjoong     6 Feb 26 10:49 test.txt
hanjoong@ubuntu:~/test$ mv pack pack_bak
hanjoong@ubuntu:~/test$ tar -xvf pack.tar
pack/
pack/data05
pack/data03
pack/data02
pack/data01
pack/data04
hanjoong@ubuntu:~/test$ ls -la
total 32
drwxrwxr-x 4 hanjoong hanjoong  4096 Feb 26 11:28 .
drwxr-xr-x 7 hanjoong hanjoong  4096 Feb 26 10:48 ..
drwxrwxr-x 2 hanjoong hanjoong  4096 Feb 26 11:13 pack
drwxrwxr-x 2 hanjoong hanjoong  4096 Feb 26 11:13 pack_bak
-rw-rw-r-- 1 hanjoong hanjoong 10240 Feb 26 11:27 pack.tar
-rw-rw---- 1 hanjoong hanjoong     6 Feb 26 10:49 test.txt
hanjoong@ubuntu:~/test$

Usage: chown [OPTION]... [OWNER][:[GROUP]] FILE...
  or:  chown [OPTION]... --reference=RFILE FILE...
Change the owner and/or group of each FILE to OWNER and/or GROUP.
With --reference, change the owner and group of each FILE to those of RFILE.

  -c, --changes          like verbose but report only when a change is made
  -f, --silent, --quiet  suppress most error messages
  -v, --verbose          output a diagnostic for every file processed
      --dereference      affect the referent of each symbolic link (this is
                         the default), rather than the symbolic link itself
  -h, --no-dereference   affect symbolic links instead of any referenced file
                         (useful only on systems that can change the
                         ownership of a symlink)
      --from=CURRENT_OWNER:CURRENT_GROUP
                         change the owner and/or group of each file only if
                         its current owner and/or group match those specified
                         here.  Either may be omitted, in which case a match
                         is not required for the omitted attribute
      --no-preserve-root  do not treat '/' specially (the default)
      --preserve-root    fail to operate recursively on '/'
      --reference=RFILE  use RFILE's owner and group rather than
                         specifying OWNER:GROUP values
  -R, --recursive        operate on files and directories recursively

The following options modify how a hierarchy is traversed when the -R
option is also specified.  If more than one is specified, only the final
one takes effect.

  -H                     if a command line argument is a symbolic link
                         to a directory, traverse it
  -L                     traverse every symbolic link to a directory
                         encountered
  -P                     do not traverse any symbolic links (default)

      --help     display this help and exit
      --version  output version information and exit

Owner is unchanged if missing.  Group is unchanged if missing, but changed
to login group if implied by a ':' following a symbolic OWNER.
OWNER and GROUP may be numeric as well as symbolic.

Examples:
  chown root /u        Change the owner of /u to "root".
  chown root:staff /u  Likewise, but also change its group to "staff".
  chown -hR root /u    Change the owner of /u and subfiles to "root".

hanjoong@ubuntu:~/test$ ls -laR
.:
total 16
drwxrwxr-x 3 hanjoong hanjoong 4096 Feb 26 11:33 .
drwxr-xr-x 7 hanjoong hanjoong 4096 Feb 26 10:48 ..
drwxrwxr-x 2 root     hanjoong 4096 Feb 26 11:13 pack
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:49 test.txt

./pack:
total 28
drwxrwxr-x 2 root     hanjoong 4096 Feb 26 11:13 .
drwxrwxr-x 3 hanjoong hanjoong 4096 Feb 26 11:33 ..
-rw-rw---- 1 root     hanjoong    6 Feb 26 10:57 data01
-rw-rw---- 1 root     hanjoong    6 Feb 26 10:57 data02
-rw-rw---- 1 root     hanjoong    6 Feb 26 10:57 data03
-rw-rw---- 1 root     hanjoong    6 Feb 26 10:57 data04
-rw-rw---- 1 root     hanjoong    6 Feb 26 10:57 data05
hanjoong@ubuntu:~/test$ sudo chown -R hanjoong pack
hanjoong@ubuntu:~/test$ ls -laR
.:
total 16
drwxrwxr-x 3 hanjoong hanjoong 4096 Feb 26 11:33 .
drwxr-xr-x 7 hanjoong hanjoong 4096 Feb 26 10:48 ..
drwxrwxr-x 2 hanjoong hanjoong 4096 Feb 26 11:13 pack
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:49 test.txt

./pack:
total 28
drwxrwxr-x 2 hanjoong hanjoong 4096 Feb 26 11:13 .
drwxrwxr-x 3 hanjoong hanjoong 4096 Feb 26 11:33 ..
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:57 data01
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:57 data02
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:57 data03
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:57 data04
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:57 data05
hanjoong@ubuntu:~/test$

Usage: find [-H] [-L] [-P] [-Olevel] [-D help|tree|search|stat|rates|opt|exec] [path...] [expression]

default path is the current directory; default expression is -print
expression may consist of: operators, options, tests, and actions:

operators (decreasing precedence; -and is implicit where no others are given):
      ( EXPR )   ! EXPR   -not EXPR   EXPR1 -a EXPR2   EXPR1 -and EXPR2
      EXPR1 -o EXPR2   EXPR1 -or EXPR2   EXPR1 , EXPR2

positional options (always true): -daystart -follow -regextype

normal options (always true, specified before other expressions):
      -depth --help -maxdepth LEVELS -mindepth LEVELS -mount -noleaf
      --version -xdev -ignore_readdir_race -noignore_readdir_race

tests (N can be +N or -N or N): -amin N -anewer FILE -atime N -cmin N
      -cnewer FILE -ctime N -empty -false -fstype TYPE -gid N -group NAME
      -ilname PATTERN -iname PATTERN -inum N -iwholename PATTERN -iregex PATTERN
      -links N -lname PATTERN -mmin N -mtime N -name PATTERN -newer FILE
      -nouser -nogroup -path PATTERN -perm [+-]MODE -regex PATTERN
      -readable -writable -executable
      -wholename PATTERN -size N[bcwkMG] -true -type [bcdpflsD] -uid N
      -used N -user NAME -xtype [bcdpfls]

actions: -delete -print0 -printf FORMAT -fprintf FILE FORMAT -print
      -fprint0 FILE -fprint FILE -ls -fls FILE -prune -quit
      -exec COMMAND ; -exec COMMAND {} + -ok COMMAND ;
      -execdir COMMAND ; -execdir COMMAND {} + -okdir COMMAND ;

hanjoong@ubuntu:~$ find -name *data*
./test/pack/data05
./test/pack/data03
./test/pack/data02
./test/pack/data01
./test/pack/data04
./apache-activemq-5.14.3/data
./apache-activemq-5.14.3/data/kahadb/db.data
./apache-activemq-5.14.3/lib/optional/jackson-databind-2.6.3.jar
hanjoong@ubuntu:~$

Usage: ln [OPTION]... [-T] TARGET LINK_NAME   (1st form)
  or:  ln [OPTION]... TARGET                  (2nd form)
  or:  ln [OPTION]... TARGET... DIRECTORY     (3rd form)
  or:  ln [OPTION]... -t DIRECTORY TARGET...  (4th form)
In the 1st form, create a link to TARGET with the name LINK_NAME.
In the 2nd form, create a link to TARGET in the current directory.
In the 3rd and 4th forms, create links to each TARGET in DIRECTORY.
Create hard links by default, symbolic links with --symbolic.
By default, each destination (name of new link) should not already exist.
When creating hard links, each TARGET must exist.  Symbolic links
can hold arbitrary text; if later resolved, a relative link is
interpreted in relation to its parent directory.

Mandatory arguments to long options are mandatory for short options too.
      --backup[=CONTROL]      make a backup of each existing destination file
  -b                          like --backup but does not accept an argument
  -d, -F, --directory         allow the superuser to attempt to hard link
                                directories (note: will probably fail due to
                                system restrictions, even for the superuser)
  -f, --force                 remove existing destination files
  -i, --interactive           prompt whether to remove destinations
  -L, --logical               dereference TARGETs that are symbolic links
  -n, --no-dereference        treat LINK_NAME as a normal file if
                                it is a symbolic link to a directory
  -P, --physical              make hard links directly to symbolic links
  -r, --relative              create symbolic links relative to link location
  -s, --symbolic              make symbolic links instead of hard links
  -S, --suffix=SUFFIX         override the usual backup suffix
  -t, --target-directory=DIRECTORY  specify the DIRECTORY in which to create
                                the links
  -T, --no-target-directory   treat LINK_NAME as a normal file always
  -v, --verbose               print name of each linked file
      --help     display this help and exit
      --version  output version information and exit

The backup suffix is '~', unless set with --suffix or SIMPLE_BACKUP_SUFFIX.
The version control method may be selected via the --backup option or through
the VERSION_CONTROL environment variable.  Here are the values:

  none, off       never make backups (even if --backup is given)
  numbered, t     make numbered backups
  existing, nil   numbered if numbered backups exist, simple otherwise
  simple, never   always make simple backups

Using -s ignores -L and -P.  Otherwise, the last option specified controls
behavior when a TARGET is a symbolic link, defaulting to -P.

hanjoong@ubuntu:~/test/pack$ ln /home/hanjoong/test/test.txt /home/hanjoong/test/pack/test_link.txt
hanjoong@ubuntu:~/test/pack$ ls -la
total 32
drwxrwxr-x 2 hanjoong hanjoong 4096 Feb 26 11:46 .
drwxrwxr-x 3 hanjoong hanjoong 4096 Feb 26 11:33 ..
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:57 data01
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:57 data02
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:57 data03
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:57 data04
-rw-rw---- 1 hanjoong hanjoong    6 Feb 26 10:57 data05
-rw-rw---- 2 hanjoong hanjoong    6 Feb 26 10:49 test_link.txt
hanjoong@ubuntu:~/test/pack$ cat test_link.txt
12345
hanjoong@ubuntu:~/test/pack$

Usage: grep [OPTION]... PATTERN [FILE]...
Search for PATTERN in each FILE or standard input.
PATTERN is, by default, a basic regular expression (BRE).
Example: grep -i 'hello world' menu.h main.c

Regexp selection and interpretation:
  -E, --extended-regexp     PATTERN is an extended regular expression (ERE)
  -F, --fixed-strings       PATTERN is a set of newline-separated fixed strings
  -G, --basic-regexp        PATTERN is a basic regular expression (BRE)
  -P, --perl-regexp         PATTERN is a Perl regular expression
  -e, --regexp=PATTERN      use PATTERN for matching
  -f, --file=FILE           obtain PATTERN from FILE
  -i, --ignore-case         ignore case distinctions
  -w, --word-regexp         force PATTERN to match only whole words
  -x, --line-regexp         force PATTERN to match only whole lines
  -z, --null-data           a data line ends in 0 byte, not newline

Miscellaneous:
  -s, --no-messages         suppress error messages
  -v, --invert-match        select non-matching lines
  -V, --version             print version information and exit
      --help                display this help and exit
      --mmap                deprecated no-op; evokes a warning

Output control:
  -m, --max-count=NUM       stop after NUM matches
  -b, --byte-offset         print the byte offset with output lines
  -n, --line-number         print line number with output lines
      --line-buffered       flush output on every line
  -H, --with-filename       print the file name for each match
  -h, --no-filename         suppress the file name prefix on output
      --label=LABEL         use LABEL as the standard input file name prefix
  -o, --only-matching       show only the part of a line matching PATTERN
  -q, --quiet, --silent     suppress all normal output
      --binary-files=TYPE   assume that binary files are TYPE;
                            TYPE is 'binary', 'text', or 'without-match'
  -a, --text                equivalent to --binary-files=text
  -I                        equivalent to --binary-files=without-match
  -d, --directories=ACTION  how to handle directories;
                            ACTION is 'read', 'recurse', or 'skip'
  -D, --devices=ACTION      how to handle devices, FIFOs and sockets;
                            ACTION is 'read' or 'skip'
  -r, --recursive           like --directories=recurse
  -R, --dereference-recursive  likewise, but follow all symlinks
      --include=FILE_PATTERN  search only files that match FILE_PATTERN
      --exclude=FILE_PATTERN  skip files and directories matching FILE_PATTERN
      --exclude-from=FILE   skip files matching any file pattern from FILE
      --exclude-dir=PATTERN  directories that match PATTERN will be skipped.
  -L, --files-without-match  print only names of FILEs containing no match
  -l, --files-with-matches  print only names of FILEs containing matches
  -c, --count               print only a count of matching lines per FILE
  -T, --initial-tab         make tabs line up (if needed)
  -Z, --null                print 0 byte after FILE name

Context control:
  -B, --before-context=NUM  print NUM lines of leading context
  -A, --after-context=NUM   print NUM lines of trailing context
  -C, --context=NUM         print NUM lines of output context
  -NUM                      same as --context=NUM
      --color[=WHEN],
      --colour[=WHEN]       use markers to highlight the matching strings;
                            WHEN is 'always', 'never', or 'auto'
  -U, --binary              do not strip CR characters at EOL (MSDOS/Windows)
  -u, --unix-byte-offsets   report offsets as if CRs were not there
                            (MSDOS/Windows)

hanjoong@ubuntu:~$ grep if .profile
# This file is not read by bash(1), if ~/.bash_profile or ~/.bash_login
# if running bash
if [ -n "$BASH_VERSION" ]; then
    # include .bashrc if it exists
    if [ -f "$HOME/.bashrc" ]; then
# set PATH so it includes user's private bin if it exists
if [ -d "$HOME/bin" ] ; then
hanjoong@ubuntu:~$ grep -c if .profile
7
hanjoong@ubuntu:~$