一: Shell中循环剖析 for 循环.......
#!/bin/bash -
#==================================================================================================================
FILE: countloop.sh
USAGE: ./countloop.sh
DESCRIPTION:
OPTIONS: -------
REQUIREMENTS: ---------
BUGS: ------
NOTES: --------
AUTHOR: ---------YangGe (TOM) ,YangGe.freedom@icloud.com
ORGANIZATION:
CREATED: 2023-8-24 09:11:20
REVISION: --------
#====================================================================================================================
for i in 1 2 3 4 5 6 #循环1~6
do
echo "Thre for loop is run $i times."
done
echo "==============================================================================================================="
for linux in Debian Redhat Suse Fedora Centos7 Ubunto
do
echo "current out system is ${linux}....."
done
echo "================================================================================================================"
#!/bin/bash -
#==================================================================================================================
FILE: orcmdssub.sh
USAGE: ./forcmdssub.sh
DESCRIPTION:
OPTIONS: -------
REQUIREMENTS: ---------
BUGS: ------
NOTES: --------
AUTHOR: ---------YangGe (TOM) ,YangGe.freedom@icloud.com
ORGANIZATION:
CREATED: 2023-8-24 09:11:20
REVISION: --------
#====================================================================================================================
echo "Printing file list in /etc directory........"
for file in `ls /etc/*`
do
echo "current print file is: $file"
done
#!/bin/bash -
#==================================================================================================================
FILE: forcmdssub.sh
USAGE: ./forcmdssub.sh
DESCRIPTION:
OPTIONS: -------
REQUIREMENTS: ---------
BUGS: ------
NOTES: --------
AUTHOR: ---------YangGe (TOM) ,YangGe.freedom@icloud.com
ORGANIZATION:
CREATED: 2023-8-24 09:11:20
REVISION: --------
#====================================================================================================================
echo "Printing file list in /etc directory........"
for file in `ls /etc/*`
do
echo "current print file is: $file"
done
[root@www shelldic]# cat forvarscoutents.sh
#!/bin/bash -
#==================================================================================================================
FILE: forvarscoutents.sh
USAGE: ./forvarscoutents.sh
DESCRIPTION:
OPTIONS: -------
REQUIREMENTS: ---------
BUGS: ------
NOTES: --------
AUTHOR: ---------YangGe (TOM) ,YangGe.freedom@icloud.com
ORGANIZATION:
CREATED: 2023-8-24 09:11:20
REVISION: --------
#====================================================================================================================
filenames="/etc/my.cnf /etc/vconsole.conf /etc/rsyncd.conf /etc/sestatus.conf /usr/local/rs.conf"
上面的文件名以空格分割
for file in $filenames
do
[ -f $file ] && echo "The file $file was found.." || echo "***** ERROR: The file $file was missing.....*******"
如果是文件,则打印文件存在,如果不存在则打印丢失
done
#!/bin/bash -
#==================================================================================================================
FILE: simplenestedfor.sh
USAGE: ./simplenestedfor.sh
DESCRIPTION:
OPTIONS: -------
REQUIREMENTS: ---------
BUGS: ------
NOTES: --------
AUTHOR: ---------YangGe (TOM) ,YangGe.freedom@icloud.com
ORGANIZATION:
CREATED: 2023-8-24 09:11:20
REVISION: --------
#====================================================================================================================
for (( i = 0; i < 30; i++ )) #外循环
do
for (( j=0; j<160; j++ )) # 内循环
do
echo -n "* " #
done
echo "" #
done
二 ： while循环
#!/bin/bash -
#==================================================================================================================
FILE: whichreadfile.sh
USAGE: ./whichreadfile.sh
DESCRIPTION:
OPTIONS: -------
REQUIREMENTS: ---------
BUGS: ------
NOTES: --------
AUTHOR: ---------YangGe (TOM) ,YangGe.freedom@icloud.com
ORGANIZATION:
CREATED: 2023-8-24 09:11:20
REVISION: --------
#====================================================================================================================
file=$1 # 将位置参数1的值赋值给变量file
if [ $# -lt 1 ];then # 如果脚本未指定参数,则打印使用方法并退出运行
echo "Usage: $0 FILEPATH"
exit
fi
while read -r line # 使用read命令从标准输入读取文件的一行,并赋值给变量line
do
echo $line # 打印读取的行
done < "$file"
[root@www shelldic]# cat whilereadfile.sh
#!/bin/bash -
#==================================================================================================================
FILE: whichreadfile.sh
USAGE: ./whichreadfile.sh
DESCRIPTION:
OPTIONS: -------
REQUIREMENTS: ---------
BUGS: ------
NOTES: --------
AUTHOR: ---------YangGe (TOM) ,YangGe.freedom@icloud.com
ORGANIZATION:
CREATED: 2023-8-24 09:11:20
REVISION: --------
#====================================================================================================================
file=$1 # 将位置参数1的值赋值给变量file
if [ $# -lt 1 ];then # 如果脚本未指定参数,则打印使用方法并退出运行
echo "Usage: $0 FILEPATH"
exit
fi
while read -r line # 使用read命令从标准输入读取文件的一行,并赋值给变量line
do
echo $line # 打印读取的行
done < "$file"
输出测试：
[root@www shelldic]#./whilereadfile.sh /etc/sudo.conf
Default /etc/sudo.conf file
Format:
Plugin plugin_name plugin_path plugin_options ...
Path askpass /path/to/askpass
Path noexec /path/to/sudo_noexec.so
Debug sudo /var/log/sudo_debug all@warn
Set disable_coredump true
Sudo plugins:
The plugin_path is relative to ${prefix}/libexec unless fully qualified.
The plugin_name corresponds to a global symbol in the plugin
that contains the plugin interface structure.
The plugin_options are optional.
The sudoers plugin is used by default if no Plugin lines are present.
Plugin sudoers_policy sudoers.so
Plugin sudoers_io sudoers.so
Sudo askpass:
An askpass helper program may be specified to provide a graphical
password prompt for "sudo -A" support. Sudo does not ship with its
own passpass program but can use the OpenSSH askpass.
Use the OpenSSH askpass
#Path askpass /usr/X11R6/bin/ssh-askpass
Use the Gnome OpenSSH askpass
#Path askpass /usr/libexec/openssh/gnome-ssh-askpass
Sudo noexec:
Path to a shared library containing dummy versions of the execv(),
execve() and fexecve() library functions that just return an error.
This is used to implement the "noexec" functionality on systems that
support C<LD_PRELOAD> or its equivalent.
The compiled-in value is usually sufficient and should only be changed
if you rename or move the sudo_noexec.so file.
#Path noexec /usr/libexec/sudo_noexec.so
Core dumps:
By default, sudo disables core dumps while it is executing (they
are re-enabled for the command that is run).
To aid in debugging sudo problems, you may wish to enable core
dumps by setting "disable_coredump" to false.
Set to false here so as not to interfere with /proc/sys/fs/suid_dumpable
Set disable_coredump false