UNIX COMMANDS

 CAL [month] year                   Print calendar

               cal                             displays calendar

                                                                            month = 1 to 12

                                                                            year = 1 to 9999

 CAT                                                       Concatenate and Print

               $cat file                       displays file

 CD                                                         Change working directory

               cd                              return to login directory

               cd dirname                      change working directory to dirname

 CHMOD                                                 Change permission mode for file

               chmod [who] op-code permission... file...

                who:

                               o       others

                               g       group

                               u       Login owner

                               a       all of above

                op-code:

                               +       add permission

                               -       remove permission

                               =       assign absolute permission

                permission:

                               r       read

                               w       write

                               x       execute

 CP                                                         Copy File

                cp file1 file2                  copy file1 and name new copy as file2

DIFF                                                      Differential File Comparator

               diff [options] file1 file2      find difference between file1 and file2

                options:

                               -b      ignore spaces and tabs in comparison

                               -e      ed script option

                               -f      opposite order script

                               -h      simple, fast, less-rigorous comparison

ECHO                                                    Echo arguments

               echo [arg]...                   echo arg to standard output

FIND                                                      Find Files

               find pathname-list... condition...

                options:

                               -atime n                last accessed day n

                               -exec cmd               execute cmd if file meets conditions

                               -group gname            file owner gname

                               -links n                number of links to file

                               -mtime n                last modified day n

                               -name file              specify filename

                               -newer file             file modified more recently than file

                               -ok cmd                   execute cmd only on 'y' response

                               -print                  display the file pathname

                               -size n                 file size in blocks

                               -type c                 specify file-type

                                                                                            b       block

                                                                                            c       character

                                                                                            d       directory

                                                                                            f       plain file

                               -user uname             file owner uname

GREP                                                    Search file for pattern

               grep [options] pattern file...  find lines in file matching pattern

                options:

                               -c      count of matching lines

                               -e      use if pattern begins with '-'

                               -h      header display suppressed

                               -l      list of filenames containing pattern

                               -n      line number of lines which match

                               -v      variant: all lines except matches

                               -y      lowercase pattern will match uppercase

LP                                                         Line print spooler

               lp [options] file...            place file in line printer queue

                options:

                               -c                      make copy of file for queue

                               -ddestprn               specify destprn as destination printer

                               -fformname              use the form specified by formname

                               -m                      report by mail when printed

                               -nx                     print x copies

                               -r                      remove file after placing in queue

                               -ttitle                 specify title as banner

                               -w                      write message on terminal after printing

LS                                                         List Contents of Directory

               ls [options] name...            list contents of directory

                options:

                               -a      all entries

                               -d      directory status information

                               -l      long format

                              -r      reverse order listing

                               -s      size in blocks

                               -t      sort by time modification

                               -u      sort by last access time

                               -x      multi-column across page

MAN                                                      On-line Manual

               man [options] section title     locates and displays pages of unix manual

                options:

                               -a      all matching title

                               -f      first matching title

                               -w      prints pathname to manual section

MESG                                                   Permit or Deny Messages

               mesg [options]          report or set write permission on terminal

                options:

                               -n      deny non-user write permission

                               -y      enable non-user write permission

MKDIR                                                   Make a Directory

               mkdir dirname...                create directory

MV                                                        Move a file or directory

               mv file1 file2                  change name of file1 to file2

               mv dir1 dir2                    rename dir1 directory to dir2 directory

               mv file... dname                move one or more files to directory dname

PASSWD                                               Change Login Password

               passwd                          change your password

PR                                                         Print File with Pagination

               pr [options] file...            formatted printing of file...

                options:

                               -a                      multi-column across page

                               -d                      double space output

                               -f                      use form-feed character as page break

                               -h "title"              customized page heade title

                               -ln                     page length n lines

                               -m                      print all files... in multiple columns

                               -n                      produce n-column output

                               +n                      start printing at page n

                               -sc                     seperate columns with character c

                               -t                      no header printed

                               -wn                     page width n characters

PS                                                         Process Status

               ps [options] processnumber      print information about active processes

               options:

                               -a      all processes except group leaders and non-terminal processes

                               -e      all processes

                               -l      long listing

PWD                                                      Print Working Directory

               pwd                             display current working directory

RM                                                        Remove files or directories

               rm [options] file...            remove one or more files

               options:

                               -f      force removal of write-protected files

                               -i      interactive delete

                               -r      recursively delete directory

SORT                                                    Sort or Merge Files

               sort [options] [+pos1] [-pos2] [-ofileout] filein...

               options:

                               -b      ignore leading blanks and tabs

                               -c      check if sorted

                               -d      dictionary order

                               -f      ignore case

                               -i      ignore non-printable characters in non-numeric comparisons

                               -M      compare as months

                               -m      merge the files, input files are already sorted

                               -n      sort on first numeric field

                               -r      reverse order of sort

                               -tx     field seperator is x

                               -u      eliminate duplicate lines

               +pos1, -pos2            restrict sort key to beginning at pos1 and ending at pos2

               -ofileout               write output to outfile

TAIL                                                      Deliver last part of a file

               tail [+-n] file                 copy file to stdout +n from beginning to -n from end of file

TEE                                                       Pipe fitting

               tee [options] file...           divert a copy into file...

               options:

                               -a      append to file

                               -i      ignore interrupt signals

                               -u      unbuffered output

UNIQ                                      Remove repeated lines in a sorted file

                uniq [options] input [output]     remove repeated adjacent lines in input file when copying to output file 

               options: 

                               -u             display lines not repeated in input 

                               -d             display one copy of repeated lines in input 

                               -c             precede each line with number of times repeated 

                               -n             ignore the first n fields 

                               +n            ignore the first c characters

 WC                                                       Word Count 

                               wc [options] file... count lines, words and characters in file... 

               options: 

                               -c             count characters 

                               -l              count lines 

                               -w            count words

 WHO                                     Who is on the system 

               who                                        list user login name, terminal and login time 

WRITE                                   Write to another user

                write user [ttyname]                write to user on terminal, ttyname the ttyname is optional. 

HEAD

This is used to view the first few lines of a file. It accepts a switch specifying the number of lines to view.

NEWS

The news command keeps the user informed of current events.

DF

it reports number of free disk blocks, and i-nodes

DU

Summarizes disk usage in a specified directory hierarchy

LN

Creates a hard link (default), or a soft link (with -s option)

MOUNT, UMOUNT

Attaches, or detaches, a file system (super user only)

MKFS

Constructs a new file system (super user only)

FSCK

Evaluates the integrity of a file system (super user only)

FINGER

finger displays information about one or more Linux users. GNU finger supports a single host that can act as the finger server host in sites that have multiple hosts. This host collects information about who is logged into other hosts at that site. Thus, a query to any machine at another site will return complete information about any user at that site.

NICE

            run a program with modified scheduling priority  

SET

Typing the set command will print out a list of all the current shell environments. This is a list of all the variables and settings that the shell currently has.

SHELL VARIABLES

The shell supports user and system variables. An example of system variables are,

        PS1             system prompt

        PS2             secondary line shell prompt

        HOME            home directory

        LOGNAME         login name

Variables are assigned values using the = sign.