:%s/NAME/name/

:1-10s/NAME/name/

:1,10s/NAME/name/

:s/NAME/name/

$?

$$

$#

$@

change

setfscl

chown

chmod

this

that

this other

this that other

test $a -eq $b

test a -eq b

test $a -equal $b

test $a = $b

sleep 1 & echo $!

sleep 1 & echo $?

sleep 1 & echo $#

sleep 1 & echo $$

ls -n

ln

ln -s

link -s

ls -lrt file1

ls -lR file1

find . -s file1

find . -name file1

$# will print the same

$? will print the same

$! will print the same

$$ will print the same

goodbye

hello

hellox

hellogoodbye

if the output of “cmp -s file1 file2” is not zero

if the output of “cmp -s file1 file2” is zero

if the output of “cmp -s file1 file2” is one

if the output of “cmp -diff file1 file2” is zero

True

False

0

1

2

100

cp -i

cp -r

cp -p

cp -R

ctrl+c then bg

ctrl+z then bg

ctlr+m then bg

ctrl+z then fg

list all ordinary files in current dir that have been modified within last 24 hours

list all ordinary files in current dir that have been modified within last 4 days

list all ordinary files in current dir that have been modified within last 48 hrs

list all ordinary files in current dir that have been modified within last 2 hrs

inode

filter

kernel

shell

echo “hello world” > temp.txt

echo “hello world” | tee temp.txt

echo "hello world">tmp.txt|tee tmp.txt

echo "hello world">tmp.txt|print

ls -l | grep ^d

ls | grep dir

ls | grep ^d

pwd

head +10 file

cat file

tail -10 file

head -10 file