Lab46 Wiki

■ $PATH….X

■ Job control…….x

■ wildcards……x

■ tab completion…..x

■ Cron/Crontab…….x

■ Pattern Matching………x

■ Regular Expressions…….x

■ Shell Scripting…..x

shell scripting

shell scripting is a small program essentialy that contains commands such as command line task such as grep, ls, mv, and cp. when you run the script it it excute these for you instead of typing all theses things.

ls ~ df who

is in script.sh

 lab46:~$ ./script.sh
Desktop          archive2.zip          count.c     mail
Documents        archives              data        motd
Downloads        archivescombined.tar  date        multitask.lab.txt
Maildir          at                    dateyears   output
Music            badname               devel       phenny
Pictures         badname.tgz           file        phenny.tar.bz2
Public           bin                   forloop.sh  script.sh
Templates        botscript.sh          guess1.sh   src
Videos           class_notes           lab1        src.bak
age.sh           classlog.c            lab2        the answer.txt
archive1.tar.gz  count                 loop.sh
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/xvda1             4128448   2522072   1396664  65% /
tmpfs                   784300         0    784300   0% /lib/init/rw
udev                    755640        36    755604   1% /dev
tmpfs                   784300         4    784296   1% /dev/shm
/dev/xvda2              253871     12859    227905   6% /tmp
nfs:/home            2930056576 1434124544 1495932032  49% /home
nfs:/lib/mail        2930056576 1434124544 1495932032  49% /var/mail
skinney1 pts/8        2012-03-17 11:36 (cpe-24-94-52-91.stny.res.rr.com)
rmatsch  pts/16       2012-03-17 11:46 (user-10bj433.cable.mindspring.com)
jjohns43 pts/24       2012-01-23 12:18 (cpe-74-65-82-173:S.0)
smalik2  pts/29       2012-03-17 10:49 (cpe-69-205-204-88.stny.res.rr.com)
skinney1 pts/35       2012-03-16 10:15 (65-124-85-125.dia.static.qwest.net)
mfaucet2 pts/65       2012-03-09 17:09 (55:S.0)
smalik2  pts/27       2012-01-25 14:53 (cpe-69-205-204-88:S.0)
wedge    pts/28       2012-03-17 10:02 (telstar.lair.lan)
jdavis34 pts/22       2012-03-06 12:57 (cpe-69-205-141-69:S.0)
jjohns43 pts/82       2012-02-27 11:03 (cpe-74-65-82-173:S.0)
lab46:~$

PATH is an environmental variable that specifies a set of directories where executable programs are located.

lab46:~$export PATH=$PATH:/home/rmatsch/src/unix

Job control allow you to have the system work on a job in the background while you do something else . If you are simply trying to get logged out, but have encountered the “There are stopped jobs” message

Useful Commands control-z Stop (don't kill) the foreground job, and then return to the shell

Check the status of jobs in the current session ps -u username Check the status of processes, including those from other sessions. On BSD systems, use 'ps -gx'. kill -9 %1 Kill a job, by specifying its job number after the percent sign kill -9 123 Kill a process, by specifying its process id (PID) number bg Run the most recently stopped job in the background fg Bring most recently background job to the foreground fg %1 Bring a job to foreground by specifying its job number after the percent sign

A daemon is a computer program that runs in the background as a process, instead of running in the foreground. below is an example of a deamon running in back ground and a command to look at the root processes.

inetd or init

 lab46:~$ ps -u root
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root         1  0.0  0.0   8356   720 ?        Ss   Jan17   0:41 init [2]
root         2  0.0  0.0      0     0 ?        S    Jan17   0:00 [kthreadd]
root         3  0.0  0.0      0     0 ?        S    Jan17   0:05 [migration/0]
root         4  0.0  0.0      0     0 ?        S    Jan17   0:08 [ksoftirqd/0]
root         5  0.0  0.0      0     0 ?        S    Jan17   0:00 [watchdog/0]
root         6  0.0  0.0      0     0 ?        S    Jan17   0:04 [migration/1]
root         7  0.0  0.0      0     0 ?        S    Jan17   0:03 [ksoftirqd/1]
root         8  0.0  0.0      0     0 ?        S    Jan17   0:00 [watchdog/1]
root         9  0.0  0.0      0     0 ?        S    Jan17   5:40 [events/0]
root        10  0.0  0.0      0     0 ?        S    Jan17   3:53 [events/1]
root        11  0.0  0.0      0     0 ?        S    Jan17   0:00 [cpuset]
root        12  0.0  0.0      0     0 ?        S    Jan17   0:00 [khelper]
root        13  0.0  0.0      0     0 ?        S    Jan17   0:00 [netns]
root        14  0.0  0.0      0     0 ?        S    Jan17   0:00 [async/mgr]
root        15  0.0  0.0      0     0 ?        S    Jan17   0:00 [pm]
root        16  0.0  0.0      0     0 ?        S    Jan17   0:00 [xenwatch]
root        17  0.0  0.0      0     0 ?        S    Jan17   0:00 [xenbus]
root        18  0.0  0.0      0     0 ?        S    Jan17   0:06 [sync_supers]
root        19  0.0  0.0      0     0 ?        S    Jan17   0:07 [bdi-default]
root        20  0.0  0.0      0     0 ?        S    Jan17   0:00 [kintegrityd/0]
root        21  0.0  0.0      0     0 ?        S    Jan17   0:00 [kintegrityd/1]
root        22  0.0  0.0      0     0 ?        S    Jan17   0:00 [kblockd/0]
root        23  0.0  0.0      0     0 ?        S    Jan17   0:00 [kblockd/1]
root        24  0.0  0.0      0     0 ?        S    Jan17   0:00 [kseriod]
root        27  0.0  0.0      0     0 ?        S    Jan17   0:00 [kondemand/0]
root        28  0.0  0.0      0     0 ?        S    Jan17   0:00 [kondemand/1]
root        29  0.0  0.0      0     0 ?        S    Jan17   0:02 [khungtaskd]
root        30  0.0  0.0      0     0 ?        S    Jan17   0:20 [kswapd0]
root        31  0.0  0.0      0     0 ?        SN   Jan17   0:00 [ksmd]
root        32  0.0  0.0      0     0 ?        S    Jan17   0:00 [aio/0]
root        33  0.0  0.0      0     0 ?        S    Jan17   0:00 [aio/1]
root        34  0.0  0.0      0     0 ?        S    Jan17   0:00 [crypto/0]
root        35  0.0  0.0      0     0 ?        S    Jan17   0:00 [crypto/1]
root        38  0.0  0.0      0     0 ?        S    Jan17   0:00 [khvcd]
root       123  0.0  0.0      0     0 ?        S    Jan17   0:14 [kjournald]
root       170  0.0  0.0  10408     4 ?        S<s  Jan17   0:00 udevd --daemon
root       222  0.0  0.0  10404     4 ?        S<   Jan17   0:00 udevd --daemon
root       223  0.0  0.0  10404     4 ?        S<   Jan17   0:00 udevd --daemon
root       355  0.0  0.0      0     0 ?        S    Jan17   0:49 [rpciod/0]
root       356  0.0  0.0      0     0 ?        S    Jan17   0:00 [rpciod/1]
root       373  0.0  0.0      0     0 ?        S<   Jan17   0:00 [kslowd000]
root       374  0.0  0.0      0     0 ?        S<   Jan17   0:00 [kslowd001]
root       375  0.0  0.0      0     0 ?        S    Jan17   0:28 [nfsiod]
root       395  0.0  0.0      0     0 ?        S    Jan17   0:03 [kjournald]
root       495  0.0  0.0   6748   596 ?        Ss   Jan17   0:00 dhclient -v -pf
root       788  0.0  0.0  43220     4 ?        S    Jan17   0:00 supervising sys
root       789  0.0  0.1  51592  2912 ?        Ss   Jan17   0:39 /usr/sbin/syslo
root       890  0.0  0.0  10208   104 ?        Ss   Jan17   0:00 /usr/sbin/inetd
root       921  0.0  0.0  43112   344 ?        Ss   Jan17   0:05 /usr/sbin/sshd
root      1014  0.0  0.0      0     0 ?        S    Jan17   0:00 [nfsv4.0-svc]
root      1037  0.0  0.0   5928     8 hvc0     Ss+  Jan17   0:00 /sbin/getty 384
root      1780  0.0  0.1  74000  2296 ?        SN   Mar09   0:00 /USR/SBIN/CRON
root     15461  0.0  0.1  59236  2076 ?        Ss   Jan19   0:12 /usr/sbin/cron
root     21168  0.0  0.0      0     0 ?        S    Mar14   0:01 [flush-202:1]
root     25915  0.0  0.2  89100  3932 ?        SNs  02:23   0:00 sshd: csit2310
root     27443  0.0  0.2  89100  3964 ?        SNs  Mar16   0:00 sshd: skinney1
root     28768  0.0  0.0      0     0 ?        S    08:35   0:00 [flush-0:17]
root     29506  0.0  0.2  89100  3960 ?        SNs  10:02   0:00 sshd: wedge [pr
root     30082  0.0  0.2  89100  3988 ?        SNs  10:48   0:00 sshd: smalik2 [
root     30157  0.0  0.1  58860  2076 ?        Ss   Mar14   0:02 /usr/sbin/rpc.i
root     30213  0.0  0.1 167308  2236 ?        Ssl  Mar14   0:16 /usr/sbin/nscd
root     30246  0.0  0.2  89100  4000 ?        SNs  11:08   0:00 sshd: smalik2 [
root     30373  0.0  0.0      0     0 ?        S    11:28   0:00 [flush-202:2]
root     30418  0.0  0.2  89100  3984 ?        SNs  11:35   0:00 sshd: jdavis34
root     30435  0.0  0.2  89100  4000 ?        SNs  11:36   0:00 sshd: skinney1
root     30530  0.0  0.2  89100  3992 ?        SNs  11:46   0:00 sshd: rmatsch [
root     31447  0.0  0.1  74000  2296 ?        SN   Mar09   0:00 /USR/SBIN/CRON
root     31763  0.0  0.1  74004  1956 ?        SN   Mar14   0:00 /USR/SBIN/CRON
root     32271  0.0  0.1  74000  2296 ?        SN   Mar09   0:00 /USR/SBIN/CRON
root     32506  0.0  0.1  74000  2300 ?        SN   Mar13   0:00 /USR/SBIN/CRON
lab46:~$

cron/crontab

cron tab is a task scheduler.It is a time based which runs periodically at certain times or dates, used to automate system processes.

lab46:~$ crontab -e

 # Edit this file to introduce tasks to be run by cron.
#
# Each task to run has to be defined through a single line
# indicating with different fields when the task will be run
# and what command to run for the task
#
# To define the time you can provide concrete values for
# minute (m), hour (h), day of month (dom), month (mon),
# and day of week (dow) or use '*' in these fields (for 'any').#
# Notice that tasks will be started based on the cron's system
# daemon's notion of time and timezones.
#
# Output of the crontab jobs (including errors) is sent through
# email to the user the crontab file belongs to (unless redirected).
#
# For example, you can run a backup of all your user accounts
# at 5 a.m every week with:
# 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/
#
# For more information see the manual pages of crontab(5) and cron(8)
#
# m h  dom mon dow   command

characters that are very powerful and help a great deal when in UNIX. the special characters enable a user to control the output of commands without having to specify the exact name of a file.

* zero or more of “any” character

? used to represent one of “any” character

\ will ignore such things as space if the variable name isn't one string.

” ” (or ' ') quote the enclosed characters

[ ] character class - match any of the enclosed characters.

[^ ] inverted character class - do not match any of the enclosed characters.

Pattern matching a way to search in unix which enables the user to look for files.

Using ls(1), list files that match the following patterns: a. Only files that begin with a lowercase vowel. b. All files that end with a .s c. All files that do not start with a vowel, yet end with a .s d. Only 3 character filenames that don't end with a consonant. e. Explain your strategy and reasoning for constructing an effective pattern for each part of this question

a. Using ls in the given directory, show me how you'd list only files

   that begin with a lowercase vowel:

      ls a* e* i* o* u*

b. Using ls in the given directory, show me how you'd list only files

   that end with a .s:

      ls *.s

c. Using ls in the given directory, show me how you'd list only files

   that do not start with a vowel, yet end with a .s:

      ls  [b-d,f-h,j-n,p-t,v-z]**.s

d. Using ls in the given directory, show me how you'd list only the

   files consisting of just 3 character filenames that don't end with a
   consonant:

lab46:/var/public/unix/patterns$ ls a* e* i* o* u*
a.b.c.d.e.f.s  abd                         i3
a39487y        abe                         i4
a6.c           abf                         i5.s
a7.d           ac.s                        i6.s
a8.e           aca                         i7.s
a9.f           ad.s                        ive_got_a_beautiful_feeling
aaa            alab5.s                     o_what_a_beautiful_day
aab            alab6.s                     o_what_a_beautiful_morning.s
aac            e11                         u_2
aad            e8933                       uey
aae            e9038                       uey2
aaf            e904385                     ueya
ab.s           ee.s                        ueyai
aba            everythings_going_my_way.s  ueyed
abb            i1                          uint
abc            i2
lab46:/var/public/unix/patterns$

tab completion

tab completion is a command line feature that allows you to type some of a command and have the command line finish it when you hit the tab key. kinda like a auto complete

Demonstration of the chosen keyword.

lab46:/var/public/unix/patterns$ l (tab)
last             less             lispmtopgm       lrrdNode
lastb            lessecho         listres          ls
lastlog          lessfile         ln               lsattr
latin2ascii.py   lesskey          lnstat           lscpu
lcf              lesspipe         loadkeys         lsinitramfs
ld               let              loadunimap       lsmod
ld.bfd           lex              local            lsof
ld.gold          lexgrog          locale           lspci
ldapadd          lft              localedef        lspgpot
ldapcompare      lft.db           lockfile         lsusb
ldapdelete       lftp             lockfile-check   luit
ldapexop         lftpget          lockfile-create  lwp-download
ldapmodify       libnetcfg        lockfile-remove  lwp-dump
ldapmodrdn       libpng-config    lockfile-touch   lwp-mirror
ldappasswd       libpng12-config  loggen           lwp-request
ldapsearch       line             logger           lwp-rget
ldapurl          link             login            lxterm
ldapwhoami       links            logname          lynx
ldd              links2           logout           lynx.cur
ldrdf            linux32          look             lzmainfo
leaftoppm        linux64          lorder

regular expressions

Regular Expression Symbol . Match any character * Match 0 or more of the preceding

$ End of line or string [ ] Character class - match any of the enclosed characters [^ ] Negated character class - do not match any of the enclosed characters \< Beginning of word \> End of word

grep '^[b-d][aeiou]' /etc/passwd

be able to write a simple shell scipt that contains file manipulation, and irc bot configuration.

the objective entails making a script to do multiple task incoporatiing things which have already learned allong with new task.

have students given many task and allow students to write all of these task in a script to be performed in a single script.

tell students to creat a script to do thing they know how to do via command line and also do task they dont know.

Reflect upon your results of the measurement to ascertain my achievement i did alright but there is always room for inprovmemt.