UNIX
~~~~
Command Description
~~~~~~~ ~~~~~~~~~~~
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.
_______________________________________________________________________________
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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.
cal 01-12 (month) 0-9999 (year)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[cal] utility can be used to display a calendar of any year
from 0 to 9999 AD, and any or all of the twelve months.
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. Gee.
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.
[ls] provides directory information. [ls -l/] displays a more
complete version of the info. list.
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.