In Bash what is an alias Right Ans - User defined command:
[alias newcmd=oldcmd
what is an internal command Right Ans - Runs as part of the shell itself
what is an external command Right Ans - Exists as an executable file on the
computer
what is the $Path Right Ans - Defines a list of directories that search for a
filename when a user enters a command
Explain the following file descriptors
>
>>
2>
2>&1
< Right Ans - > - Redirects stout - creates files or overwrites
>> - Redirects stout - creates or appends to file
2> - Redirect sterr
2>&1 - Redirects sterr to stout
< - Redirects stdin
what is ~.bash_history Right Ans - Files that shows bash history commands
Explain the following environment configuration files
/etc/profile
/etc/bashrc
~/.bash_profile
~/.bashrc Right Ans - /etc/profile - generic file processed by all users upon
login
/etc/bashrc - This file is processed when subshells are started
~/.bash_profile - User specific variables that can be defined
~/.bashrc - User specific subvariables that can be defined
Explain the file system heirarchy
/
/bin
, /boot
/dev
/etc
/home
/lib, /lib64
/media, /mnt
/proc
/opt
/root
/run
/sbin
/srv
/sys
/tmp
/usr
/var Right Ans - / - root directory, where the file system tree starts
/bin - Find executable programs that are needed to repair a system. Directory
is essential during boot
/boot - Contains all files/dirs that are needed to boot
/dev - Device files that are used for physical device access
/etc - Contains configuration files
/home - local home user directories
/lib, /lib64 - shared libraries used by /boot,/bin,/sbin
/media, /mnt - Directories used for mounting devices
/proc - Gives access to kernel information
/opt - used for optional packages
/root - root home directory
/run - processes since last boot. empties when powered off
/sbin - similar to bin. used by adminstrators
/sys - used as an interface to different hardware devices that are managed by
the kernel
/srv - used for data that may be used for services such as NFS,FTP,HTTP
/tmp - contains temp files
/usr - contain subdirectories for program files, libraries for program files, and
documentation about them
/var - contains files that may change in size dynamically such as log files, spool
files and mail boxes
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