Linux Admin Basics

Question 1

Handling files

1. Create [file/directory]
2. Copy [file/directory]
3. Copy to a remote system
4. Move/Cut&Paste [file/directory]
5. Delete [file/directory]
6. Close [file]

Answer 1

1. a. cat [myfile.txt] or touch [myfile.txt]
   b. mkdir [directory]
2. a. cp [source file] [destination file&directory]
   b. cp -r [source directory] [destination directory]
3. scp OR sftp
4. a. mv [source file] [destination]
5. a. rm [myfile.txt]
   b. rm -r dir [directory] OR rmdir (removes empty directory)
6. q

Question 2

Command line

1. View all including hidden directory contents
2. Browse directories
   a. current directory
   b. parent directory
3. View current directory

Answer 2

1. ls -la
2. cd
   a. .
   b. ..
3. pwd

Question 3

Searching

1. Search for file or directory
2. Search for a string in a file
3. Go up a page within file
4. Go down a page within a file

Answer 3

1. find [file or directory] OR locate [file or directory]
2. grep -i [keyword]
3. ctrl + b
4. space bar

Question 4

Show

1. Show file
2. Show last 10 lines of file
3. Show text output of e.g. env. variable
4. Show processes
5. Show all previously run commands
6. Show disk usage

Answer 4

1. cat [file.txt]
2. tail [file.txt]
3. Echo [env. var]
4. a.ps -e (shows all processes) OR top
   b. ps - u [username] (shows processes of named user)
5. history
6. du -k or du -h

Question 5

Compressing and Archiving

1. Create a collection of files and directories in one file> archiving
2. Reduce/compress file size
3. Uncompress

Answer 5

1. a. tar - c [file] (archives file> file.tar)
   b. tar - x [file] (unarchives a file)
2. gzip [file] (creates> file.gzip)
   tar -z [file]
   tar -cz (archives&zips file creating> file.tgz)
3. gunzip [file.gz]
   tar -zxf file.tar.gz

Question 6

Install / Uninstall

1. Install packages in RPM
2. Delete packages in RPM
3. a Find available packages
4. List installed packages
5. Install packages in Debian
6. Remove packages in Debian

Answer 6

1. yum install [package in directory]
2. yum remove [package in directory]
3. a yum search [name of package]
4. rpm -qa
5. a. apt install [package in directory]
   b. dpkg [package] (installs local package)
6. apt remove (package in directory)

Question 7

Moving files to remote systems

1. Transfer files
2. Transfer files and view remote directories
3. Graphical clients

Answer 7

1. pscp [options] [user@]host:source target
   a. Putty secure client scp
   b. Download PSCP.EXE from Putty download page.
   c. Open command prompt and type set PATH=
   d. In command prompt point to the location of the pscp.exe using cd command.
   e. Type pscp.
   f. Use the following command to copy file form remote server to the local system
   pscp [options] [user@]host:source target.
2. Use secure ftp:
   a. sftp [remote-system IP] (login to remote syste)
   b. cd [target-directory] (change to remote directory)
   c. ls -l (confirm you have read permissions for file)
   d. get [filename] (copy file)
   e. bye (end connection)
3. a. WinSCP
   b. FileZilla
   d. Cyberduck

Question 8

Environment Variables

1. Show all env var
2. Show where a particular env. var is located
3. Set env. var
4. Remove an env var
5. Make env var. persist after startup

Answer 8

1. printenv
2. echo $[env var]
3. a. cd [directory of env var]
   b. [env var]=[target env path]
4. unset [env var]
5. Go to one of the three locations and edit the file:
   /etc/environment&raquo_space;> JAVA_PATH=/usr/local/java
   /etc/.bashrc&raquo_space;> export PATH=”$JAVA_PATH:$PATH”
   ~/.pam_environment&raquo_space;>PATH DEFAULT=/usr/bin:usr/local/bin

Question 9

Linux Directory

/bin
/sbin
/etc
/home
/opt
/tmp
/usr
/var
/cdrom
/mnt
/proc

** potential logs for third party software

Answer 9

/bin – executable files aka essential binaries
/sbin – system binaries
/etc ** – host specific system config
/home – home directories
/opt ** – config file for third party application software
>bin
>etc
>lib
>log
/tmp – temporary files deleted on boot
/usr ** – sharable and read only files
>bin
>etc
>lib
>log
/var ** – var. data files generated by system or vendor
/cdrom – mount point for CDs
/mnt – mount point f external file systems
/proc – running processes

Question 10

Attach a folder/directory to a home directory

Remove the attached directory

Answer 10

> mount [mountable folder] [destination directory]

> umount [mounted folder]