asadprodhan/Navigating_a_Linux_computer

Navigating a Linux computer

Navigating a Linux computer

AUTHOR: Dr Asad Prodhan https://asadprodhan.github.io/

Q: How to use my Linux computer remotely?

• Open a ssh client. For example, MobaXterm
• Click on ‘Session’ located at top-left corner
• Fill up the following boxes and click ‘OK’:
  • Remote host
  • Specify username
  • SSH-browser type as SFTP protocol

Figure 1: MobaXterm.

Q: How to enable sftp on the sidebar in the MobaXterm?

• Go to MobaXterm Session settings > SSH > Fill up Remote host > Specify username > Select ‘SFTP protocol’ from the ‘SSH-browser type’ drop down menu

Q: How to transfer data between a remote computer and your local laptop?

Option 1: Drag and drop using the left panel of your MobaXterm

Option 2: sftp

• sftp username@remote_host:/destination_directory
• ‘put -r’ to transfer data from local to remote
• ‘put -ar’ to transfer data that failed in the first attempt
• ‘get -r’ to transfer from remote to local

GREP

Code/ Symbol	Command/ Elaboration	Function/ Example
grep	Search and print lines containing a word	grep 'salmon' File.tsv > FileSalmon.tsv
grep --color	Search text	grep --color "Lunch" File1.txt
grep --color -A 2 "word"	Print 2 lines after the match	grep --color -A 2 "word" File1.txt
grep --color -B 2 "word"	Print 2 lines before the match	grep --color -B 2 "word" File1.txt
grep --color -C 2 "word"	Print 2 lines before and after the match	grep --color -C 2 "word" File1.txt
grep -v "word"	Find everything except 'word'	grep -v "word" File1.txt
grep -c "[WW]ord"	Count the occurrence of 'W/word'	grep -c "[WW]ord" File1.txt

SED

Code/ Symbol	Command/ Elaboration	Function/ Example
sed -n 3p	Extract the 3rd line	sed -n 3p File1.txt
sed -n 3-5p	Extract the 3rd to 5th lines	sed -n 3-5p File1.txt
sed 's/Find/Replace/g' File.txt	Find and replace	sed 's/Ishmael/Dave/g' File1.txt; "Ishmael" replaced by "Dave"

AWK

Code/ Symbol	Command/ Elaboration	Function/ Example
awk '{print $1,$2,$3,$4,$5,$7}'	Subset columns 1-5, 7	awk '{print $1,$2,$3,$4,$5,$7}' file.tsv
awk '{print $3}'	Print third column	awk '{print $3}' File.tsv
awk '{print $3,"\t"50}'	Print third column and add 50 at reach row; /t is tab space	awk '{print $3,"\t"50}' File.tsv
awk '{print $3,"\t"$3+1}'	Print third column and add 1 with all row values	awk '{print $3,"\t"$3+1}' File.tsv

CUT

Code/ Symbol	Command/ Elaboration	Function/ Example
cut -f1,2,3,4,5,7	Subset columns 1-5, 7	cut -f1,2,3,4,5,7 File1.txt

NANO

Code/Symbol	Function/Example
alt+sht+$	wraps lines
alt+sht+y	highlights syntex
alt+sht+#	puts line number
fg	to return to nano
ctrl+K	deletes entire line
ctrl+A	moves the cursor at the beginning of the line
ctrl+E or Alt+/	moves the cursor at the end of the line
Ctrl+Shift+- 7406148	Jump to line number 7406148
Ctrl+W	Search for words

PUTTY

Code/Symbol	Function/Example
psftp> get -r *	download one file
psftp> mget -r *	download multiple files
psftp> put -r *	upload one file
psftp> mput -r *	upload multiple files

TMUX

Code/Symbol	Function/Example
tmux > press enter	start tmux session
Ctrl-b d	detach from the tmux session but the session will continue running in the background
tmux list	list all the active tmux sessions. Left-hand column shows the session numbers
tmux attach -t 1	logging in into tmux session 1
tmux kill-session -t 1	terminating tmux session 1