Wednesday, July 30, 2008

UNIX COMMAND Bible

Franken's UNIX Command Bible is suitable for the UNIX
dilettante, as well as for the hardcore hack. Provides
easy reference for those hard-to-remember commands.
Attractive print-out fits well in any decor.





CommandDescription
  • awk
  • Search for a pattern within a file. Includes a built-in programming language.
  • bdiff
  • Compares two large files.
  • bfs
  • Scans a large file.
  • cal
  • Displays a calendar.
  • cat
  • Concatenates and prints files.
  • cc
  • C compiler.
  • cd
  • Change directory.
  • chgrp
  • Changes a file's group ownership.
  • chmod
  • Changes a file's access permissions.
  • chown
  • Changes the individual ownership of a file.
  • cmp
  • Compares two files; diplays the location (line and byte) of the 1st difference between these.
  • comm
  • Compares two files so as to determine which lines are common to both.
  • cp
  • Copies a file to another location.
  • cu
  • Calls another UNIX system.
  • date
  • Returns the date and time.
  • df
  • Displays free space in the file system.
  • diff
  • Displays the differences between two files or directories.
  • diff3
  • Displays the differences between three files or directories.
  • du
  • Reports on file system usage.
  • echo
  • Displays its argument.
  • ed
  • Text editor.
  • ex
  • Text editor.
  • expr
  • Evaluates its argument which is generally a mathematical formula.
  • f77
  • FORTRAN compiler.
  • find
  • Locates the files w/ specified characteristics.
  • format
  • Initializes a floppy disk.
  • grep
  • Searches for a pattern within a file. (see awk)
  • help
  • Salvation.
  • kill
  • Ends a process.
  • ln
  • Used to link files.
  • lpr
  • Copies the file to the line printer.
  • ls
  • Displays info. about one or more files.
  • mail
  • Used to receive or deliver e-mail.
  • mkdir
  • Creates a new directory.
  • more
  • Displays a long file so that the user can scroll through it.
  • mv
  • Used to move or rename files.
  • nroff
  • Used to format text.
  • ps
  • Display a process's status.
  • pwd
  • Display the name of the working directory.
  • rm
  • Removes one or more files.
  • rmdir
  • Deletes one or more directories.
  • sleep
  • Causes a process to become inactive for a specified length of time.
  • sort
  • Sort and merge one or more files.
  • spell
  • Finds spelling errors in a file.
  • split
  • Divides a file.
  • stty
  • Display or set terminal parameters.
  • tail
  • Displays the end of a file.
  • troff
  • Outputs formatted output to a typesetter.
  • tset
  • Sets the terminal type.
  • umask
  • Allows the user to specify a new creation mask.
  • uniq
  • Compares 2 files. Finds and displays lines in one file that are unique.
  • uucp
  • UNIX-to-UNIX execute.
  • vi
  • Full screen editor.
  • wc
  • Displays details in the file size.
  • who
  • Info. on who else be online.
  • write
  • Used to send a message to another user.


That's the Summary. Now print it out, if you'd like. Good for fast
referencing. Following the Summary is a more in-depth look at each
of the commands already listed.
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awk program filenames
awk -f programfilenames filenames
The [awk] utility can be used to find any lines in a file which
match a certain pattern; once found, these lines can be processed.
In the first configuration, the program that [awk] is to
execute is specified in the command line. In the second,
the program is stored as the file given in programfilename.
The -f option instructs [awk] to read this file.



[bdiff]
is used to compare files too large for [diff]. See
[diff] for the format.



bfs filename

[bfs] is used to scan a large file to determine where to split
it into smaller files.



cat filename

[cat] can be used to examine a short file. See [more] for
lengthier files.



number[cc]

The [cc] command changes the entire current line, or a group
of lines starting with the current line. [number] represents
the number of old lines to be deleted.



cd directory name

The [cd] command causes the current working directory to be
changed. The [directory name] can be either a full or partial
path name.



chgrp groupname filename

This command changes the group ownership of a file.



chmod {ugoa} {+-} {rwx}

The [chmod] utility changes a file's access permissions. [u]
specifies the user or owner's login name, [g] specifies a group
and [o] indicates all others. [a] indicates the user, group,
and all others; c'est the default. [+] adds permission; [-]
deletes it. [r] indicates read, [w] write, and [x] execute.



chown individualname filename

[chown] changes the individual ownership of a file (see chgrp).



cmp filename1 filename2

[cmp] is one of the four principle UNIX file comparison utilities.
It compares 2 files, and returns the positions where they differ.



comm -options filename1 filename2

The [comm] utility, in comparing two files, produces three
columns of output. The first contains lines unique to the
first file, the second, lines unique to the second, and the
third column, lines common to both files. By placing the
numbers [1], [2], and/or [3] in the [options] position, any
one (or more) of these columns can be suppressed.



cp sendingfile receivingfile

The [cp] command copies a file. [sendingfile] is the file to be
copied, [receivingfile] is the file to which it is copied.



diff [options] filename1 filename2
Again, a file comparison utility. However, with [diff], the
differences are displayed as instructions that can be used
to edit the files so that they are identical.



diff3 filename1 filename2 filename3

Similar to [diff], [diff3] is unique in that it can compare three files.



ed filename
One of the UNIX's three editing utilities, [ed] is a basic line editor. I'm sure there are other files that will explain how to use [ed]. Thus, I'll confine myself to a rough outline:
e filename ........... edit a different file
f filename ........... changes the currently specified file.
h .................... provides explanation of errors.
I
text ................. inserts text before the current line.
line,linel ........... lists the specified lines.
line,linen ........... displays specified lines, preceded by
their line numbers.
q .................... exit from [ed]
w .................... writes buffer to current filename.
+ or - ............... +number of lines closer to end
-number of lines closer to beginning.



expr formula

Utility which evaluates an expression.




find directory searchcriteria parameter actioncriteria parameter

The [find] utility can be very useful indeed, especially when
confronted by a UNIX with countless files. Basically, this
command finds files which meet certain criteria, and then
performs an operation (such as printing the files). Search
criteria consists of the following:


Criteria Parameter Description
~~~~~~~~ ~~~~~~~~~ ~~~~~~~~~~~
-name filename Files whose names match [filename]
will meet this criteria.
-type filetype Files whose type matches that specified
[b] block special will meet criteria.
[c] character spec. file
[d] directory file
[f] plain file
-links +/- x Files with # of links indicated by
+ or - x meet this criteria.
-user login name Files belonging to user with given
or user ID # login name or ID # meet criteria.
-group group name Files belonging to group with given
or group ID # group name or ID # meet this criteria.
-size + or - x Files greater than +x bytes or less
than -x bytes meet this criteria.
-atime + or - x Files not accessed within +x days,
accessed within -x days, or acc-
essed x days ago meet criteria.
-mtime + or - x Files NOT modified within +x days,
modified within -x days, or modified
x days ago will meet this criteria.
-newer filename Files modified more recently than
[filename] meet this criteria.
Action Criteria " "
~~~~~~~~~~~~~~~ ~ ~
-print - When search criteria are met, path
name of the file is displayed.
-exec command{ }\; Executes given command when search
criteria are met. { } indicates file-
name, [\;] ends the command.
-ok command{ }\; Exactly like -exec, except user is
prompted [y] or [n] before command.




grep -options searchstring filenames

Another search command, this for a particular string of chars.




ln original new
[ln] establishes a file link. For this utility, [original] repre-
sents the filename to be linked, [new] the filename of the new
link to the original.





mail username username
This utility allows e-mail to be sent to other system users.

mail

Simply typing [mail] checks the user's own mailbox.
When sending mail, several items must be set:
~s text ............ sets the subject field
~c user names ...... sends other users carbon copies of mail
m user names ....... activates the compose mode, with the
specified users as the message's recipients.
~h ................. displays and allows editing of all headers.
^D ................. ends message editing; sends mail.
~r filename ........ places file in body of message (keen command)

Reading One's Own Mail:
h number or range ....... causes specified headers to be displayed
p message # ............. displays entire message
d number or range ....... deletes specified messages
u number or range ....... undelete specified mail during SAME
mail session (messages removed after q)
q ....................... leave the post office




mkdir directoryname

[mkdir] allows creation of a subdirectory, for your dining
enjoyment.



more filename
For longer files, [more] is a convenient utility. It will display
the first screen of file data and then stop, allowing the user
to control scrolling henceforth.





mv oldfilename newfilename

The [mv] utility can be used simply to rename a file, or...


mv filea fileb... directory
[mv] can also be used to move files to a new directory, provided
the directory exists, and you have write access to it.




ps -options
The [ps] command, by itself, displays the status of each active
process controlled by your terminal. This status report includes
the Process Identification Number (PID), the terminal (TTY), the
time the process has been executing (TIME), and the command line
used to execute the process (CMD).
[ps]'s three options include -a (displays info. on active processes
controlled by any terminal), -x (info. on ALL active processes), and
-l (an extensive status report on all active processes).




pwd

[pwd] command displays the present working directory.




rm filename

[rm] removes a file. More than one file can be specified.




rmdir directoryname

This utility removes a directory, an EMPTY directory (save the
hidden files).




sleep seconds

The [sleep] utility causes a process to become inactive for a
certain period of time. Max. seconds is 65,536 (about 18 hrs).




sort -options filenames

[sort] merges and sorts files. Without options, [sort] orders
files by the ASCII codes of the characters at the beginning
of each line. Options include -b (leading blanks ignored), -d
(only letters, digs, and blanks considered; "dictionary sort"),
-f (case ignored), -n (numerical sort [for numerical data]), and
-r (a reverse sort).




split -size original resulting

[split] divides a large file into smaller ones. [size] refers to the number of lines the resulting files contain, [original] is the name of the orig. file, and [resulting] represents the prefix name assigned to the newly created files.




umask ugo

[umask] changes the file CREATION mask (see [chmod] for already existing files). Here, [u] represents the owner's access
permission, [g] the group's a.p., and [o] the a.p. for all others.


[uucp] (UNIX to UNIX copy) can be used to send files to a
remote UNIX, or retrieve files from the remote system.
Other UNIX comm commands include [cu] (which establishes contact
with another system), and [uux] (UNIX to UNIX execute; allows
commands to be executed on a remote system).




wc -options filenames

The [wc] utility displays file-size information. This includes
the number of lines, words, and characters. By chosing the
-l, -w, or -c options, the information can be limited to only
line, word, or character number.




who

A very useful command (which some systems respond to even before a user is actually logged on), [who] displays a list of users
currently online. This list includes the user's name, terminal
device # (tty), and the log-in time. [who am i] displays info.
only on the user who executed the command.


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Alright. You may have noticed that this isn't EXACTLY a Bible. I
took the liberty of omitting some of the command explanations.
But, if anyone REALLY wants to know more about [vi], or [stty],
or (perhaps more justifiably) have a more comprehensive guide
to the mail system, I'll be glad to write some 'by request'
text files.

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