Linux+ LX0-103

tar

(know) "tape archiver" archives files. common used in combination with a compression tool such as gzip, xz, or bzip2 to combine several files into a zipped file commonly referred to as a tarball. Whenever you run tar, you use only one command with one or more qualifiers. Collectively, the commands and qualifiers are called options. newer uses of tar don't use - so read the question carefully. tar [options] destination/tar_file_name files-to-archive commands -c or --create Creates an archive -A or --concatenate Appends tar files to an archive -r or --append Appends non-tar files to an archive -u or --update Appends files that are newer than those in an archive -d --diff or --compare Compares an archive to files on disk -t or --list Lists an archive's contents -x or --extract or --get Extracts files from an archive qualifiers -C or --directory dir Changes to directory dir before performing operations -f or --file [host:]file Uses the file called file on the computer called host as the archive file -g or --listed-incremental file Performs an incremental backup or restore, using file as a list of previously archived files -M or --multi-volume Creates or extracts a multi-volume archive -p or --preserve-permissions Preserves all protection information -P or --absolute-paths Retains the leading / on filenames -v or --verbose Lists all files read or extracted; when used with --list, displays file sizes, ownership, and time stamps -W or --verify Verifies the archive after writing it -z or --gzip or --ungzip Compresses an archive with gzip -j or --bzip2 Compresses an archive with bzip2 -J or --xz Compresses an archive with xz compression options -c or --stdout Compresses or decompresses to standard output -d or --decompress Forces bzip2 to decompress -z or --compress Forces bzip2 to compress -q or --quiet Prevents all non-essential warning messages from being displayed -v or --verbose Shows the compression ratio of each file processed ex $ tar cvfz /media/pen/my-work.tgz ∼/my-work tar: Removing leading '/' from member names /home/Christine/my-work/ /home/Christine/my-work/punch_list.txt /home/Christine/my-work/project_a354 /home/Christine/my-work/project_m1321 /home/Christine/my-work/project_c923 $ $ ls -l /media/pen/my-work.tgz -rw-rw-r--. 1 Christine Users 780 Sep 25 10:44 my-work.tgz $ $ ls -l ∼/my-work total 24 -rw-rw-r--. 1 Christine Users 9972 Sep 25 10:30 project_a354 -rw-rw-r--. 1 Christine Users 3324 Sep 25 10:30 project_c923 -rw-rw-r--. 1 Christine Users 2216 Sep 25 10:30 project_m1321 -rw-rw-r--. 1 Christine Users 218 Sep 25 10:27 punch_list.txt

tee

(know) command used to split input so that it can be displayed on standard output(monitor) and in as many files as you specifiy. $ echo $PATH | tee path.txt /usr/lib64/qt-3.3/bin:/usr/local/bin:/bin:/usr/bin: /usr/local/sbin:/usr/sbin:/sbin:/home/Christine/bin $ $ cat path.txt /usr/lib64/qt-3.3/bin:/usr/local/bin:/bin:/usr/bin: /usr/local/sbin:/usr/sbin:/sbin:/home/Christine/bin $ tee will generally overwrite existing data so if you just want to add additional data use the -a flag to append(add to end)

Reasons for RPM package not to install on a RPM machine

-different versions of RPM utilities -different dependencies than the other distro -different naming on the dependent packages -distro dependent scripting and config files - different files in packages

history

-lists command history for last 500 commands !! lists last command and executes it ! and the command number in history will list and execute that command history -c clears the history stored in the env HISTFILE or .bash_history

Redirect Operators

> Creates a new file containing standard output. If the specified file exists, it's overwritten. No file descriptor necessary. >> Appends standard output to the existing file. If the specified file doesn't exist, it's created. No file descriptor necessary. 2> Creates a new file containing standard error. If the specified file exists, it's overwritten. File descriptor necessary. 2>> Appends standard error to the existing file. If the specified file doesn't exist, it's created. File descriptor necessary. &> Creates a new file containing both standard output and standard error. If the specified file exists, it's overwritten. No file descriptors necessary. < Sends the contents of the specified file to be used as standard input. No file descriptor necessary. << Accepts text on the following lines as standard input. No file descriptor necessary. <> Causes the specified file to be used for both standard input and standard output. No file descriptor necessary.

cut

By Byte: The -b list or --bytes=list option cuts the specified list of bytes from the input file. (The format of list is described shortly.) By Character: The -c list or --characters=list option cuts the specified list of characters from the input file. In practice, this method and the by-byte method usually produce identical results. (If the input file uses a multibyte encoding system, though, the results won't be identical.) By Field: The -f list or --fields=list option cuts the specified list of fields from the input file. By default, a field is a tab-delimited section of a line, but you can change the delimiting character with the -d char, --delim=char, or --delimiter=char option, where char is the character you want to use to delimit fields. Ordinarily, cut echoes lines that don't contain delimiters. Including the -s or --only-delimited option changes this behavior so that the program doesn't echo lines that don't contain the delimiter character.

Deleting Text

Ctrl D- deleted text under cursor Ctrl K- deletes all text from cursor to the end of the line Ctrl X and backspace- deletes all text from cursor to beginning

Transposing Text

Ctrl T transposes the letter under the cursor and the letter before it Esc T transposes the words under the cursor and before the cursor

Invoke Text Editor

Ctrl X followed by Ctrl E will bring up the text editor

Changing Case

Esc C text under cursor to upper case Esc U text at and after cursor to upper case Esc L text at and after cursor to lower case

Ctrl S

Forward in the search results of Ctrl R

Ctrl R

Reverse search for a command by typing any part of it

groupadd

add group -g Group ID -p Password -r Create system group

useradd

adds new user -D Outputs defaults -c Comment -e When to expire account -f Number of days after password expiration to disable account -g Default group -G Additional groups -M Do not create home directory -m Set home directory -p Define password -r Create system user -s Set default shell -u Define UID

&&

and

xargs

builds a command from its standard input. xargs [options] [command [initial-arguments]] ex # find / -user Christine | xargs -d "\n" rm find / -user Christine - finds all files in directory tree( / ) that belong to Christine and outputs them into xargs xargs then takes the output from find and creates a new line with each entry -d "\n" and finally removes them with the rm command

bzip/bunzip

bzip; compresses files

` backtick `or $( )

can be used like xargs but you can't manipulate it as well. # rm `find / -user Christine` or you can use $( ) # rm $(find / -user Christine)

cd

change directory cd ~ takes you to the home directory

chmod

change file mode, can only be used by root or file owner chmod [options] [mode[,mode...]] filename... -R or --recursive changes all files in directory if directory mode is changed to change by octal form. ls -l file.dat -rw-rw-r--. 1 Christine Users 199 Sep 15 14:36 file.dat chmod 644 file.dat ls -l file.dat -rw-r--r--. 1 Christine Users 199 Sep 15 14:36 file.dat you can set SUI SGID and Sticky with a forth digit at the front of the three digit number, use these numbers 1 Sticky bit permission 2 SGID permission 4 SUID permission to change in symbolic mode A mode's symbolic representation, by contrast, consists of three components: A code indicating the permission set to modify (the owner, the group, other, and so on) A symbol indicating whether you want to add, delete, or set the mode equal to a stated value A code specifying what the permission should be Permission set code u Owner g Group o Other a All Change type code + Add - Remove = Set equal to Permission to modify code r Read w Write x Execute X Execute only if the file is a directory or already has execute permission s SUID or SGID t Sticky bit u Existing owner's permissions g Existing group permissions o Existing other permissions ex chmod a+x bigprogram rw-r--r-- rwxr-xr-x chmod ug=rw report.tex r-------- rw-rw---- chmod o-rwx bigprogram rwxrwxr-x rwxrwx--- chmod g=u report.tex rw-r--r-- rw-rw-r-- chmod g-w,o-rw report.tex rw-rw-rw- rw-r-----

chown

change files ownership chown [options] [newowner][:newgroup] filenames ex # chown sally:skyhook forward.odt -R or --recursive changes all files in directory if directory ownership is changed. can only be used by root or file owner

passwd

change/set password -S View password settings -l Locks account -u Unlocks account -d Remove password -n Set days before password change -x Set maximum days before password change -w Days to warn prior to password reset -i Days to wait after expired password to disable account

expand

changes tabs to spaces. some programs don't work well with tabs so sometimes you need to change them to spaces -t num or --tabs=num will allow you to change the number of spaces that equals a tab

clear

clears the screen

bash shell

command completion when pressing tab command history

if

conditional statements in bash scripting -d See if directory exists -e See if file exists -f See if file exists and it is a regular file -G See if file exists and it is owned by a defined group -h See if file exists and it is symlinked -L See if file exists and it is symlinked (same as -h) -O See if file exists and it is owned by defined UID -r See if file exists and has read permissions -w See if file exists and had write permissions -x See if file can be executed

unexpand

converts multiple spaces to tabs, default is 8 spaces. num is the number of spaces. -t num or --tabs=num

cp

copy cp [options] source destination -f or --force; will overwrite any existing files with the same name -i or --interactive; will ask to overwrite -p or --preserve; preserves file ownership -R or --recursive; will copy files under directories -a or --archive; preserve symlinks -u or --update Copy only if original file is newer cp will preserve the file name unless specified otherwise ex ls -F file.dat new_file.dat TempDir/ $ $ cp file.dat TempDir/ $ $ cp file.dat TempDir/file2.dat $ $ ls TempDir/ file2.dat file.dat

userdel

delete user -r Delete home folder

sed

directly modifies a file's contents, sending the changed file to standard output sed [options] -f script-file [input-file] sed [options] script-text [input-file] input file is the file you want to modify script-file is the script you want to run script-files sould be placed in single quotation marks = -displays current line number a\text -append text to file i\text - Insert text into file r filename -append text from filename into the file c\text -replace the selected range with the provided text s/regexp/replacement -text that matches the regular expression (regexp) with replacement w filename -write the current pattern space to the specified file q -immediately quit the script, but print the current pattern space Q -immediately quit the script ex sed 's/2012/2013/' cal-2012.txt > cal-2013.txt -replaces 2012s with 2013s and outputs to cal-2013.txt know

w

displays user system information

who

displays who is logged in -b Last boot time of machine -m Hostname and associated user -r Run level for current user -q Number of logged-in users -a All

Ctrl G

end search

gzip/gunzip

gzip; compresses files

info

improved manual pages

join

joins two files line by line usually using the first field as the joining field seperating with a space ex join listing1.1.txt listing1.2.txt

paste

joins two files together line by line but outputs all data in the line(unlike join where it joins the first or specified field) and places a tab between them

ls

list contents of directory ls [options] [files] -a or --all List all files, including hidden files -l List files, including details such as owner and permissions, size, and creation date -p Adds a / to the end of directories -R or --recursiveEnable recursion, including all sub-directories -F or --classify displays the file extension: examples below / Directory * Executable | Named pipe = Socket @ Symbolic link --color displays the files in a color code -d or --directory list directories

find

locate file in system. Can be slow but is very accurate. find [path...] [expression...] -name [pattern(filename)] searches by filename, wildcards can be used here -perm [mode] searches for files with certain permission modes. This can be done in octal or symbolic mode. if you use a + before mode it will search for any file with any of the specified permission bits, if you use a - it will look for only the exact match of permission bits. -size [n] search for file by size usually 512 bytes -gid [GID] searches by groupd id or you can search by name using the -group name option. -uid [UID] searches by user id or -user name searches by name. -maxdepth [levels] searches a specified depth into the filesystem. (know)

dig

look up IP addresses and DNS names

man

manual pages 1 Executable programs and shell commands 2 System calls for the kernel 3 Library calls 4 Device files 5 File formats 6 Games 7 Misc. 8 Programs only run by the root user 9 Kernel routines -k Returns all documentation containing search keyword (apropos)

groupmod

modify group -g GID -p Password

usermod

modify user account -c Comment -e Expire date -f Days after password expiration to disable account -G Add groups -l Change username -L Lock account -m Move home directory -p Change password -u Set user ID -U Unlock account

Ctrl A(left arrow) or Ctrl E (right arrow)

move right or left in command one word at a time

mv

move; used to move or rename files mv [options] source destination -m Set permissions mode -p Force recursion -i or --interactive; will ask to overwrite -u or --update Copy only if original file is newer -f or --force; will overwrite any existing files with the same name

nl

numbers the lines in a file -b style or --body-numbering=style-numbering for bulk lines with style code -h style or --header-numbering=style- numbers header with style code -f style or --footer-numbering=style-numbers footer with style code -d=code or --section-delimiter=code-tells n1 how to identify a new page -p or --no-renumber-doesn't restart the count on a new page -n format or --number-format=format option, where format is ln (left justified, no leading zeros), rn (right justified, no leading zeros), or rz (right justified with leading zeros) styling code t The default behavior is to number lines that aren't empty. You can make this default explicit by using a style code of t. a This style code causes all lines to be numbered, including empty lines. n This style code causes all line numbers to be omitted, which may be desirable for headers or footers. pREGEXP This option causes only lines that match the specified regular expression (REGEXP) to be numbered. Regular expressions are described later in "Using Regular Expressions.''

od

octal dump-displays the octal form of files

less(updated version of more)

opens file in a vim-like environment for viewing, allows for viewing a document in command line a page a few lines at a time. Pressing the spacebar moves forward through the file a screen at a time. Pressing Esc followed by V moves backward through the file a screen at a time. The Up and Down arrow keys move up or down through the file a line at a time. You can search the file's contents by pressing the slash (/) key followed by the search term. For instance, typing /portable finds the first occurrence of the string portable after the current position. Typing a slash followed by the Enter key moves to the next occurrence of the search term. Typing n alone repeats the search forward, while typing N alone repeats the search backward. You can search backward in the file by using the question mark (?) key rather than the slash key. You can move to a specific line by typing g followed by the line number, as in g50 to go to line 50. When you're done, type q to exit from the program.

head

output the first ten lines of a file

cat

outputs the contents of a file and joins files joining files cat first.txt second.txt > combined.txt cat combined.txt data from first txt data from second text Display Line Ends: If you want to see where lines end, add the -E or --show-ends option. The result is a dollar sign ($) at the end of each line. Number Lines: The -n or --number option adds line numbers to the beginning of every line. The -b or --number-nonblank option is similar, but it numbers only lines that contain text. Minimize Blank Lines: The -s or --squeeze-blank option compresses groups of blank lines down to a single blank line. Display Special Characters: The -T or --show-tabs option displays tab characters as ∧I. The -v or --show-nonprinting option displays most control and other special characters using carat (∧) and M- notations.

tail

outputs the last ten lines of a file -c #ofbytes or --bytes=num lets you specify the # of bytes you want to see instead of the last ten lines -n #oflines or --lines=#oflines lets you see a specified number of lines -f --follow- keeps the file open and display new lines as they're added(log files) --pid=[pid] terminates tracking

id

outputs user and group IDs for a user -u Show only UID -g Show only GID -G Show all groups to which a user belongs -Gn Group name

whoami

outputs username of current user

RPM Naming

packagename-a.b.c-x.arch.rpm a.b.c.- version number x -build number arch- arcitecture rpm- file extension

pr

print processing, formats files into printer friendly documents. -[# of columns] or --columns=# of columns- multicolum output -d or --double-space - double spaces file to be printed -f, -F, --form-feed- outputs a form feed character between pages if your printer is having issues printing the document -l [# of lines] or --length=[# of lines] sets the lenghth of page in lines -h text or --header=text replaces the filename and sets the header, if you want spaces in the header inclose it in "" and omit the header with -t or --omit-header -o [number of characters] or --indent=[number of characters] sets the left margin -w [number of characters] or --width [number of characters] sets width of document(default is 72) ex cat -n /etc/profile | pr -d | lpr

pwd

print working directory

echo

prints out what you specify, whether a string or $ followed by env variable to see the variables

ps

process status ps behavior can be modified with the PS_PERSONALITY env --help gives info on command -A or -e lists all process x displays just the process owned by the used that typed the command -u user, U user, --User will display processes ran by specified user -f, -l, j, l, u, and v all expand the information displayed about the processes -H, -f, and --forest displays the hierarchy of the relationships between the processes -w and w displays the output wider than the default 80 columns, helpful if you output to a text document ps w > ps.txt -u Define user Output PID process id PPID parent process id TTY teletype identifies terminal used TIME total time CPU used for all processes %CPU time for certain process NI process priority RSS memory use %MEM memory use Share shared memory Command command used to start process

init 6

reboots the operating system

Pipes

redirects the first programs output to be input for a second program and is done using the vertical line | symbol ex first | second ex first | second | third | ect...

fmt

reformats text files to fit your display -width, -w width, and --width=width allow you to change the length of lines (default is 75 characters)

rm

remove rm [options] files -r, -R or --recursive Enable recursion -i or --interactive; will ask to overwrite -f or --force; will overwrite any existing files with the same name

uniq

removes duplicate lines.

ip addr

replaces ifconfig on newer systems

free

reports on system memory

apropos

returns all documentation containing the defined command

whatis

returns available man pages for command

uname

returns information related to the system -s Displays kernel name -n Displays hostname -r Kernel release number -v Kernel version number -m Hardware architecture -p Processor architecture -i Hardware platform -o Operating system -a All information

sudo

run command as root

grep

search for string -i Case insensitive -n Include line number in output

env

show environmental variables for current user

ifconfig

shows NIC for network card; configures network settings

last

shows last command used by defined user

top

shows list of current applications/processes, and system usage h and ? Help k Input process ID to kill r Change process priorety p Sort by CPU usage M Sort by memory usage q quits top s change dispaly updates i-ignores idle or zombie processes -d [time of delay] delays updates 5 sec -p pid monitor specific process -n (# of updates)

which

shows location of application

netstat

shows network status -a All listening and non-listening sockets -i Network interface statistics -l Listening sockets -s Summary of each protocol

halt

shuts down operating system

init 0

shuts down operating system

shutdown

shuts down the system -H Halts the machine -P Power off -r Reboot -h Equivalent to powering off, overridden by --halt -k Send warning, but perform no actions -c Cancel a shutdown hh:mm shuts down at certain time +[#ofminutes] for minutes in the future

reboot

shuts down, then restarts the system

set

similar to env; works with environment variables

sort

sorts text in file -r or --reverse Sort in reverse order -n or --numeric-sort Sort numerically -f or --ignore-case- Ignores case -M or --month-sort Sorts by three letter month all caps -k or --key-field [#] Allows you to change the field it sorts by(default is 1st column)

split

split a file into two or more parts. -b sizeor --bytes=size -breaks file into pieces of size bytes -c=size or --line-bytes=size -allows you to break the file into bytes with out breaking the line as long as the size is longer than the length of the line -l lines or --lines=lines splits files into chunks with the specified number of lines

su

substitute user

pwconv

syncs /etc/passwd and /etc/shadow

exit

terminates all current processes, including shell

Ctrl D

terminates programs that require command line input

traceroute

traces the route a packet takes

tr

translate- change individual character based off of sets. Searches document for specified letter and replaces it with letter in second set tr [options] set1 set2 ex tr BCJ bc < listing1.1.txt B would be replaced by b C would be replaced by c J would be replaced by b because the process starts over again. also accepts [:alnum:] (all numbers and letters) [:upper:] (all uppercase letters) [:lower:] (all lowercase letters) [:digit:] (all digits) A-M - a through m inclusive

/dev/null

trash file, good place to send all unwanted error messages with a redirect Program 2> /dev/null

finger

used to find out information regarding a user

touch

used to update the last file-modification time, last inode change time, and the last access time, if the file does not exist it will create an empty file touch [options] files -a or --time=atime changes only the access time -m or --time=mtime changes just the modification time -c or --no-create won't create a file if one doesn't exist -t [timestamp] sets the time to the specified time and is given in the form MMDDhhmm[[CC]YY][.ss] -r [reffile] or --[reference=reffile] replicates another files timestamp

Checksums(Package Management/System)

used to verify the validity of the installed software

searching for strings

using [ ] will search for any characters in the [ ] ex d[oa]g would search for dog and dag search for range by [2-5] . represents any character so a.l would search any three character combo with a and l at the end ^ is start of line $ is end of line * zero or more occurrences + one or more occurrences ? zero or one occurrence .* between two strings will search for only strings that have both strings specified A.*Lincoln would result in Abe Lincoln and Abraham Lincoln | searchs of one or the other use ( ) for sub expressions ex I like (dogs | cats) = I like dogs or I like cats to search for strings that inclus special characters you must escape them with \ ex www\.nfm\.com

pwck

verifies the integrity of the password files

route

view routing tables

type

will display whether the command is built in, external, or alias. where

wc

word count --lines (-l) --words (-w) --bytes (-c) --chars (-m) option You can also learn the maximum line length with the --max-line-length (-L) option

head and tail combination

you can used head and then pipe it to tail to display a certain range of lines in a document. ex head -n 15 sample.txt | tail -n 5

zip/unzip

zip; compresses files