1)Find command:-

find . -name a.txt

Find Read-Only Files

find / -perm /u=r

find sss -name c.txt

find -type d -name sss

find ~ -name “a.txt”

#Find all Empty Directories
find /tmp -type d -empty

. File all Hidden Files

find /tmp -type f -name “.*”

find / -size 50M

2)pg Command:-

pg a.txt

clear screen

pg -c a.txt

do not display “EOF”

pg -e a.txt

3)more command :-

overlaping and clearing window not scrolling

more -c a.txt

display “Press space to continue “q” to quit

more -d a.txt

cat a.txt | more
ls | more

4)less command:-(allow scrolling)
Ctrl + f : forwards one window
Ctrl + d : forwards half window
Ctrl + b : backwards one window
Ctrl + u : backwards half window
j : forward by one line
k : backward by one line

less a.txt

5)head command:-

head -5 a.txt

6)tail command:-
tail -5 a.txt

7)wc command :-
wc -l a.txt
wc -c a.txt
wc -w a.txt

8)touch command
-a:-This option changes the access time only
-m:-This option changes the modification time only.
-r:-Uses the access and modification times from the reference file.

touch a
touch b
stat a
touch -m a b
stat a

touch -r a.txt b.txt
touch m.txt a.txt -m

set the time of m replace a

touch -c -d “16 sep” doc2

This is used to update access[-c] and modification[-d: date string] time

touch -d “2 hours ago” filename
touch test{1..10}

=)regular expression searching command
1)grep command:-(global regular expression print)

grep “m” a.txt
grep “M” a.txt
grep -i “M” a.txt #case insensitive
grep -c “M” a.txt #line count
grep -n “M” a.txt #line number
grep -w “MM” a.txt # word

grep -f a.txt b.txt #mathching of two file
grep -L “unix” * #file names that matches & pattern

2)fgrep command:-fixed-character strings in a file
fgrep “mm” a.txt
fgrep -c “m” a.txt #line number
fgrep “m” *.txt
fgrep -l “@a” a.txt #print filename
fgrep -n “@a” a.txt #print line number
fgrep -x “a” a.txt #display only lines matched entirely.

3)egrep command:-
egrep “mital” * #globally search
egrep “m” a.txt
egrep -c “mm” a.txt #linenumber mathched
egrep -l “mm” a.txt # print filename
egrep -n “mm” a.txt # print linenumber
egrep -r “m” m.txt egrep -r “m” . #recursively searching whole root

=>working with columns and fields
1)cut:-
cat > stat.txt
Andhra Pradesh
Arunachal Pradesh
Assam
Bihar
Chhattisgarh
ctrl+z

cut -b 1,2,3 stat.txt
cut -b -3 stat.txt
cut -c 2,3 stat.txt

cat > b.txt
01234:567;89
abcd:drg;ij
ctrl+z

cut -d “;” -f1 b.txt //-f column name
cut -d “:” -f2 b.txt
who | cut -c 1-2

2)paste:-
paste a.txt b.txt
paste -d “%” a.txt b.txt
paste -d “1,” a.txt b.txt c.txt
cat stat.txt | paste

3)join:-
cat > a.txt
1 aaa
2 vvv
^Z
cat > b.txt
1 xxx
2 ccc
^Z
join a.txt b.txt
join a.txt b.txt > l.txt

=>
1)sort command:-
sort -r a.txt #reverse
sort -n a.txt #numerical character
sort -u a.txt # duplicate remove display
sort -c a.txt #if already sorted no output
sort -k2 a.txt #particular column
sort -m a.txt # sort monthwise

2)unique command:-
cat > music
i love music
i love music
i love music

3)uniq music
uniq -u music #unique line
uniq -d music #duplicate line
uniq -c music # count

redirection and piping

ls – l >hello #output(stdout)
cat >> out.txt #append data
cat >> out.txt < l.txt # input data (stdin)
cat file.txt | grep “mm” a.txt
cat m.txt | more

comparing file

cat > a
This is a Line1
^z
cat > b
This is a Line2
^z

1)cmp:-
cmp a b #byte

2)comm:-‘comm’ command is used to compare two files or streams. By default, it displays three columns, first displays non-matching items of the first file, second indicates the non-matching item of the second file, and the third column displays the matching items of both files.

comm a b #linebyline

3)diff:-
diff a b # >line < line

=>changing information to file
1)tr[translate)

cat file | tr [a-z] [A-Z]
at b.txt | tr ‘hello’ ‘HELLo’
cat file | tr [:lower:] [:upper:]
echo “Welcome To Geetanjali” | tr [:space:] “\t”
tr -d W <<< “Welcome to Geetanjali” #remove “W”
echo “my ID is 73535” | tr -d [:digit:] #remove digit
echo “my ID is 73535” | tr -cd [:digit:] #complete digit
echo “hello world” | tr -d ‘ ‘
echo -e “hello\nworld” | tr -d ‘\n’

2)sed (stream editor programme)

cat > a.txt
unix is great os. unix is opensource. unix is free os.
learn operating system.
unix linux which one you choose.
unix is easy to learn.unix is a multiuser os.Learn unix .unix is a powerful.
^z

sed ‘s/unix/linux/’ a.txt
sed ‘s/unix/linux/2’ a.txt #change 2 line
sed ‘s/unix/linux/g’ a.txt #globally replacement

3)od:-
od -b a.txt #convert file in octal format
od -c a.txt #convert character format

MATHEMATICAL CALCULATION

BC command:-

x=10
y=20
echo $x+$y | bc

factor command:-

factor 10

MONITORING INPUT OUTPUT

tee command:-
cat > a
1
2
3
cat >b
4
5
6
wc -l a |tee -a b

who | tee a.txt # content remove and data
who | tee -a a.txt #add existing file

script command:-(record all the terminal activities)
script a
date
time
cal
exit
cat a

DATE & TIME RELATED COMMAND

cal
cal 2022

date +“%A” #display weekday
display date in mm/dd/yy
date +“%D”

COMMUNICATION COMMAND

wall l.txt #write a message to all users
wall Submit Your UNIX Assignment Tomorrow.

write stud #send message on users

mail -s “hello world” some@gmail.com

finger mital #show information of users

mesg #control write access to your terminal
mesg [y/n]

The ping command sends an echo request to a host available on the network.

ping www.google.com
ping 216.58.203.4
ping localhost

PROCESS RELATED COMMANDS
ps #display about active process
ps -f #full display
ps -u mital #specific user

nice #set the priority of the process
nice -10 gnome-terminal

kill #located in (/bin/kill)
kill -l #to display all available signal
kill 1024

at 12:15 #to schedules a command to be run once at a particular time.
at tuesday +2 hours

crontab -l #view logged in current user enteries in crontab

sleep 10s
sleep 1m

S= for second (the default)
m=for minutes.
h= for hours.
d= for days.
EXAMPLE:

Create file ‘test.sh’ and run with sh
echo “display Message After 10Second”
sleep 10
echo “Welcome”

wait

top #active linux Processes.