var1=$[ $var1 - 1 ]
done
var1=100
until [ $var1 -eq 0 ]
do
echo $var1
var1=$[ $var1 - 25 ]
done
#文件数据的循环
IFSOLD=$IFS
IFS=$'n'
for entry in `cat /etc/passwd`
do
echo "Values in $entry -"
IFS=:
for value in $entry
do
echo " $value"
done
done | more
for file in /home/hanxi/*
do
if [ -d "$file" ]
then
echo "$file is directory"
elif
echo "$file is a file"
fi
done > output.txt
读取参数
#!/bin/bash
name=`basename $0`
echo the commane entered is : $name
c_args=$#
echo count args:$c_args
#取最后一个参数
echo the last parameter is ${!#}
echo all parameter: $*
echo all parameter: $@
count=1
for param in "$@"
do
echo "$@ parameter #$count = $param"
count=$[ $count + 1 ]
done
#getopts
while getopts :ab:c opt
do
case "$opt" in
a) echo "Found the -a option";;
b) echo "Found the -b option, with value $OPTARG";;
c) echo "Found the -c option";;
*) echo "Unknown option : $opt";;
esac
done
shift $[ $OPTIND - 1 ]
count=1
for param in "$@"
do
echo "Parameter $count: $param"
count=$[ $count + 1 ]
done
read -p "Please enter your age:" age
echo age:$age
if read -t 5 -p "Please enter your name: " name
then
echo "Hellp $name,welcome to my script"
else
echo
echo "sorry ,too slow!"
fi
read -n1 -p "Do you want to continue [Y/N]?" answer
case $answer in
Y | y) echo
echo " fine, continue on...";;
N | n) echo
echo OK,Good bye
exit;;
esac
echo "This is the end of the script"
read -s -p "Enter your password: " pass
echo
echo "Is your password really $pass?"
#读取文件
count=1
cat for.txt | while read line
do
echo "Line $count: $line"
count=$[ $count+1 ]
done
echo "Finished processing the file"
重定向文件描述符
#!/bin/bash
#永久重定向
exec 9>&2
exec 2>testerror
echo "this will in testerror">&2
exec 2<&9
exec 9<&0
exec 0<testin
count=1
while read line
do
echo "Line #$count:$line"
count=$[ $count + 1 ]
done
exec 0<&9
#重定向文件描述符
exec 3>&1
