basic bash learning 1

发布时间：2020-12-16 01:39:41 所属栏目：安全来源：网络整理

导读：1) a function to check the free memory: [[email?protected] ~]$ function checkmem(){ echo -n "The amount of free memeory is " free |head -2|tail -1|awk ‘{print $4}‘ }[[email?protected] ~]$ checkmemThe amount of free memeory is 107940 2) u

1) a function to check the free memory:

[[email?protected] ~]$ function checkmem(){
> echo -n "The amount of free memeory is "
> free |head -2|tail -1|awk ‘{print $4}‘
> }
[[email?protected] ~]$ checkmem
The amount of free memeory is 107940

2) using for loop to print the odd number from 1 to 99

for number in {1..99..2}
do
echo $number
done

3)? If and case

#!/bin/bash
read X
read Y
if (( $X > $Y )); then
printf "X is greater than Y"
elif (( $X == $Y )); then
printf "X is equal to Y"
else
printf "X is less than Y"
fi

#!/bin/bash
read p
case $p in 
Y|y) echo "YES" ;;
N|n) echo "NO" ;;
esac

4. delete the function name from terminal

[[email?protected] ~]$ unset -f checkmem
[[email?protected] ~]$ checkmem
bash: checkmem: command not found...
[[email?protected] ~]$

（编辑：李大同）

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