linuxshell加减

⑴ shell 编程负数加减运算

法一：用巧胡let，它几乎支持所有的运算符
let c=a+b
echo $c
结果就是1

法二拍汪：如果是Bash，可以孝贺拦用运算符$(( ))
c=$((a+b))
echo $c
结果也是1

⑵ linux最常用的Shell命令

有些人仍然会有这种愚蠢的想法，他们认为使用Linux就必须使用Linux
shell命令。胡说！你可以不懂得任何Linux命令，比如说ps，grep，ls等，但是你仍然可以使用很多现代的Linux桌面发行版。
Linux的系统管理员与桌面用户不一样，他们不像桌面用户一样使用Cinnamon，GNOME，Unity，或者KDE，他们所有的时间都是用Linux命令。
对于桌面用户来讲，若是了解一部分Linux命令，你可以更好的使用Linux，体验它的魅力，下面列举出了一些：
Shell基础：
你可以通过打开Linux的terminal（终端）来执行Shell命令。Shell的种类有很多种，例如CSH，Bourne
Shell，Korn
Shell。在现在的大多数Linux发行版中，默认的Shell一般都是Bourne
again
shell(bash)。
想看看你的Shell是哪一种，执行下面的命令
echo
$SHELL
在Linux中，$符号代表一个shell变量。所有的shell都用这种方式使用变量。有一些shell变量在你的系统启动的时候就有了默认值。例如，$SHELL；$LOGNAME是你的登录名，而$PATH变量指明了你的shell命令的搜索范围。
echo命令的作用就是打印出你的输入。如果你的输入具有shell的特殊意义，例如shell变量，他就输出变量的值。

一个重要的地方是，你要注意文本的大小写。例如，ls，是DOS的dir命令的Linux版本。这个命令列出当前工作目录下的文件列表。如果你输入的是LS，你得到的只能是“找不到命令”的错误信息。
另外在Linux
shell命令中一个重要的地方是，你可以将命令串起来。这是Unix/Linux从第一天开始就有的巧妙的特点。最简单的将命令连起来的办法就是使用“|”，我们称之为“pipe”。第一个命令的输出就是下一个命令的输入。
Linux命令有自己的语法规则：
基本的语法就像这样：
command
-option
file
例如：
ls
-la
这行命令的意义是输出当前目录的所有文件的文件名，l代表“long”，a代表“all”，有了l选项，你会发现，输出的内容比较丰富，不只包括文件
名，还有文件的访问权限，所有者，所属组等。你会发现这个命令会在屏幕上输出大量的信息，如果当前目录的文件比较多的话。
现在就是“pipe”出场的时候了。
ls
-la
|
more
你会在屏幕上看到如下信息：

你也可以在大多数Linux命令中使用通配符。通配符就是可以代表文件名中任何未知的字符或字符串。例如，*就代表任意字符串，？代表单个字符。例如：

⑶ 在Linux下，用shell编写一个简单的计算器，要实现加减乘除4个功能就行了

不用写吧，本来有个 bc 命令可用，没有下载就成.
非要写一个，zsh 的function里有一个，名 zcalc,
贴上来给你

#!/usr/bin/zsh -i
#
# Zsh calculator. Understands most ordinary arithmetic expressions.
# Line editing and history are available. A blank line or `q' quits.
#
# Runs as a script or a function. If used as a function, the history
# is remembered for reuse in a later call (and also currently in the
# shell's own history). There are various problems using this as a
# script, so a function is recommended.
#
# The prompt shows a number for the current line. The corresponding
# result can be referred to with $<line-no>, e.g.
# 1> 32 + 10
# 42
# 2> $1 ** 2
# 1764
# The set of remembered numbers is primed with anything given on the
# command line. For example,
# zcalc '2 * 16'
# 1> 32 # printed by function
# 2> $1 + 2 # typed by user
# 34
# 3>
# Here, 32 is stored as $1. This works in the obvious way for any
# number of arguments.
#
# If the mathfunc library is available, probably understands most system
# mathematical functions. The left parenthesis must be adjacent to the
# end of the function name, to distinguish from shell parameters
# (translation: to prevent the maintainers from having to write proper
# lookahead parsing). For example,
# 1> sqrt(2)
# 1.4142135623730951
# is right, but `sqrt (2)' will give you an error.
#
# You can do things with parameters like
# 1> pi = 4.0 * atan(1)
# too. These go into global parameters, so be careful. You can declare
# local variables, however:
# 1> local pi
# but note this can't appear on the same line as a calculation. Don't
# use the variables listed in the `local' and `integer' lines below
# (translation: I can't be bothered to provide a sandbox).
#
# Some constants are already available: (case sensitive as always):
# PI pi, i.e. 3.1415926545897931
# E e, i.e. 2.7182818284590455
#
# You can also change the output base.
# 1> [#16]
# 1>
# Changes the default output to hexadecimal with numbers preceded by `16#'.
# Note the line isn't remembered.
# 2> [##16]
# 2>
# Change the default output base to hexadecimal with no prefix.
# 3> [#]
# Reset the default output base.
#
# This is based on the builtin feature that you can change the output base
# of a given expression. For example,
# 1> [##16] 32 + 20 / 2
# 2A
# 2>
# prints the result of the calculation in hexadecimal.
#
# You can't change the default input base, but the shell allows any small
# integer as a base:
# 1> 2#1111
# 15
# 2> [##13] 13#6 * 13#9
# 42
# and the standard C-like notation with a leading 0x for hexadecimal is
# also understood. However, leading 0 for octal is not understood --- it's
# too confusing in a calculator. Use 8#777 etc.
#
# Options: -#<base> is the same as a line containing just `[#<base>],
# similarly -##<base>; they set the default output base, with and without
# a base discriminator in front, respectively.
#
#
# To do:
# - separate zcalc history from shell history using arrays --- or allow
# zsh to switch internally to and from array-based history.

emulate -L zsh
setopt extendedglob

local line ans base defbase forms match mbegin mend psvar optlist opt arg
local compcontext="-math-"
integer num outdigits outform=1
# We use our own history file with an automatic pop on exit.
history -ap "${ZDOTDIR:-$HOME}/.zcalc_history"

forms=( '%2$g' '%.*g' '%.*f' '%.*E' )

zmodload -i zsh/mathfunc 2>/dev/null

: ${ZCALCPROMPT="%1v> "}

# Supply some constants.
float PI E
(( PI = 4 * atan(1), E = exp(1) ))

# Process command line
while [[ -n $1 && $1 = -(|[#-]*) ]]; do
optlist=${1[2,-1]}
shift
[[ $optlist = (|-) ]] && break
while [[ -n $optlist ]]; do
opt=${optlist[1]}
optlist=${optlist[2,-1]}
case $opt in
('#') # Default base
if [[ -n $optlist ]]; then
arg=$optlist
optlist=
elif [[ -n $1 ]]; then
arg=$1
shift
else
print "-# requires an argument" >&2
return 1
fi
if [[ $arg != (|\#)[[:digit:]]## ]]; then
print - "-# requires a decimal number as an argument" >&2
return 1
fi
defbase="[#${arg}]"
;;
esac
done
done

for (( num = 1; num <= $#; num++ )); do
# Make sure all arguments have been evaluated.
# The `$' before the second argv forces string rather than numeric
# substitution.
(( argv[$num] = $argv[$num] ))
print "$num> $argv[$num]"
done

psvar[1]=$num
while vared -cehp "${(%)ZCALCPROMPT}" line; do
[[ -z $line ]] && break
# special cases
# Set default base if `[#16]' or `[##16]' etc. on its own.
# Unset it if `[#]' or `[##]'.
if [[ $line = (#b)[[:blank:]]#('[#'(\#|)(<->|)']')[[:blank:]]#(*) ]]; then
if [[ -z $match[4] ]]; then
if [[ -z $match[3] ]]; then
defbase=
else
defbase=$match[1]
fi
print -s -- $line
line=
continue
else
base=$match[1]
fi
else
base=$defbase
fi

print -s -- $line

case ${${line##[[:blank:]]#}%%[[:blank:]]#} in
q) # Exit if `q' on its own.
return 0
;;
norm) # restore output format to default
outform=1
;;
sci[[:blank:]]#(#b)(<->)(#B))
outdigits=$match[1]
outform=2
;;
fix[[:blank:]]#(#b)(<->)(#B))
outdigits=$match[1]
outform=3
;;
eng[[:blank:]]#(#b)(<->)(#B))
outdigits=$match[1]
outform=4
;;
local([[:blank:]]##*|))
eval $line
line=
continue
;;
*)
# Latest value is stored as a string, because it might be floating
# point or integer --- we don't know till after the evaluation, and
# arrays always store scalars anyway.
#
# Since it's a string, we'd better make sure we know which
# base it's in, so don't change that until we actually print it.
eval "ans=\$(( $line ))"
# on error $ans is not set; let user re-edit line
[[ -n $ans ]] || continue
argv[num++]=$ans
psvar[1]=$num
;;
esac
if [[ -n $base ]]; then
print -- $(( $base $ans ))
elif [[ $ans = *.* ]] || (( outdigits )); then
printf "$forms[outform]\n" $outdigits $ans
else
printf "%d\n" $ans
fi
line=
done

return 0

支援小数点，+ - * / , ok

⑷ linux shell两个文件数值相加

#!/bin/bash
n=1
foriin`cat1.txt`;do#手大循环1.txt
	num=`sed-n"迟旅${n}p"2.txt`#获取2.txt对行的数字
	sum=$(($num+$i))#两数毕旦竖相加
	echo$sum#打印结果
	n=$(($n+1))
done

⑸ 1.linux系统下shell脚本用case语句编写四则运算 2.linux系统下shell脚本输入数字串。进行反序输出

原来我.shell写的侍耐桐亩孝计算器：
[root@liuxiting testdir]# cat calculator.sh
#!/bin/bash
echo "usage: 1+3 <Enter> ,q <Enter> is quit"
while [ 1 ]
do
read -p "->>" str 1>>/dev/null
a=`echo $str |awk -F '+|-|*|/' '{print $1}'`
if [ $a == q ]
then
break
fi
b=`echo $str |awk -F '+|-|*|/' '{print $2}'`
o=`echo $str |grep -o "[[:punct:]]" | grep -v "\."`
case $o in
+) awk 'BEGIN{printf " =%.2f\n",'$a'+'$b'}';;
-) awk 'BEGIN{printf " =%.2f\n",'$a'-'$b'}';;
\*) awk 'BEGIN{printf " =%.2f\n",'$a'*'$b'}';;
/)if [ $b -eq 0 ]
then
echo 0 Can NOT be denominator!
continue
fi
awk 'BEGIN{printf " =%.2f\n",'$a'/'$b'}';;
#^) awk 'BEGIN{printf " =%.2f\n",'$a'**'$b'}';;
*) echo error;;
esac
done

刚刚写的老坦倒序输出：
[root@liuxiting testdir]# cat XuShuChu.sh
#!/bin/bash
echo "usage: 123456 <Enter>, q <Enter> is quit"
while [ 1 ]
do
echo -n "Pleasw enter number : "
read n
if [ $n == 'q' ]
then
break
fi
sd=0
rev=""
on=$n
echo "$n"
while [ $n -gt 0 ]
do
sd=$(( $n % 10 )) # get Remainder
n=$(( $n / 10 )) # get next digit
rev=$( echo $rev$sd)
done
echo "$on in a reverse order $rev"
done

⑹ linux用shell编1+2+3+...+n

题主你好,下面图片是代码及相应截图:

写在最后:将上面的代码写到一个文件中,比如文件名码悄为:

sum.sh

给该文件加上可执行迟弊渣权限:

chmod +x sum.sh

最后执行该文件:

./sum.sh n //n表示你要求多少个数之和

希望可以帮卜简到题主, 欢迎追问

⑺ linux shell 两个文件内容做加减法

awk'{getlines<"第一个文件"
split(s,array)
for(i=1;i<=NF;i++)$i=$i-array[5+i]
print}'第运握陆二个旁顷文件

结果皮液

9761 98.895 10 1 98.896