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Other Commands

alias aliasname='command' creates a temporary macro aliasname that executes command
chsh changes the shell
clear clears the screen
crontab maintain crontab files for individual users
env <VARIABLE=value> sets environmental VARIABLE to value (blank to show all)
kill pid kills process pid. kill –9 pid to force kill (use ps to list pid)
newgrp group sets group as the primary group owner for new files created
nice -n priority command executes the command with a specified priority
renice priority pid changes a program's priority level afterwards (see nice, ps).
script logs everything that you type to . “exit” to quit.
sleep time makes the computer wait for time. Try “sleep 30; echo Go”
telinit level specifies which runlevel to run at (0 = halt, 1 = single-user, 3
= full multi-user, 5 = X-windows, 6 = reboot)
umask permission
changes the default file permission for new files (ex: rw-r—
r--). umask 077 makes all new files rw------. The permission
that you set is subtracted from the default 666 permission (rwrw-

rw) so that umask 022 does 666 – 022 = 644 = rw-r--r--)


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KTU-FOSS LAB Solutions

Write shell scripts to show the following  ( you can write menu driven programs)
 Currently logged user and his logname ( logname)  Your current shell ( echo $SHELL)  Your home directory ( echo $HOME)  Your operating system type (echo $OSTYPE)  Your current path setting ( echo $PATH)  Your current working directory ( echo $PWD )  Show Currently logged  users ( w or who -H)      Show only the user name of logged users in the host ( users)      Details of last login ( last cek....where cek is the user id )  About your OS and version, release number, kernel version ( uname -a or  cat  /proc/version)  Show all available shells ( cat /etc/shells )  Show mouse settings (cat  /sys/class/input/mouse*/device/name )  Show computer CPU information       CPU details      ( cat /proc/cpuinfo | more )       Show information on  CPU architecture ( lscpu)       Number of Processor core ( nproc)  Show memory information       Memory details ( cat /proc/meminfo | more )       Display file system disk usage ( d…

Important Directories and Files

Important Directories
/bin                            holds the “essential” Linux commands and utilities /boot                          holds files required for boot process (kernel, vmlinuz, grub) /dev                            holds device files (hard drive, USB, CD-ROM, etc.) /etc                             holds system configuration files /etc/init.d                    holds scripts to start/stop network services /etc/rc.d                     holds system startup/shutdown scripts /etc/X11                      holds configuration files for X-windows /home                        holds user home directories (except for the root account) /lib                               holds system/shared library files /lost+found                holds files restored after system crash /mnt                            used as temporary mount point for CD-ROM, floppy, etc. /opt                              typically where large software applications are installed /proc                           holds kerne…

ER Diagrams to Table

REDUCING E-R DIAGRAM TO TABLE - A database which conforms to an E R diagram can be represented by collection of tables .For each entity set and for each relationship set in the database, we will create unique tables, which is assigned the name of the corresponding entity set or relationship sets . Each table has a no. of columns which have unique names. Each row in the table corresponds to an entity or a relationship.

REPRESENTATION OF STRONG ENTITY SET -Let E be a strong entity set with descriptive attributes a1, a2....aN . We represent this entity by table called E with N distinct columns, each of which corresponds to one of the attributes of E.

REPRESENTATION OF RELATIONSHIP SET - Let R be a relation ship set involving entity set E1,E2....En Let attribute(R) consists of 'm' attributes We can represent this relation ship set by a table called R with m distinct columns, each of which corresponds to one of the attributes in attribute (R) plus the primary key of E1..En.