if-fi
#! /bin/bash # 删除文件 和 新建文件 file=readme function delFile(){ if [ -e ./$file ];then rm -f ./$file echo "del $file ..." fi } function addFile(){ if [ ! -f ./$file ];then touch $file echo "add $file ..." fi } delFile addFile
Result:
(没有readme文件)
[work shell]$ sh if_e.sh
add readme ...
[workshell]$ sh if_e.sh
del readme ...
add readme ...
===================================================
if-else-fi
#! /bin/bash echo "press y hello" read str if [ "$str" = "y" ] || [ "$str" = "Y" ];then echo "hello" else echo "bye.." fi;
Result:
[work shell]$ sh if.sh
press y hello
y
hello
[work shell]$ sh if.sh
press y hello
n
bye..
===================================================
if-elif-else-if（函数传参1）
# !/bin/sh type=1 # 1, 2, 3(a,abc,123) function getVal(){ echo "$1" } if [ "$type" == "1" ]; then for((i=0;i<4;i++)) do eval getVal $i done elif [ "$type" == "2" ]; then echo "type" else echo "none" fi Result:
yanggang@barry$ ./param.sh
0
1
2
3
===================================================
if-elif-else-if（函数传参2）
# !/bin/sh #type=1 # 1, 2, 3(a,abc,123) function getVal(){ echo "$1" } function inputVal(){ if [ "$1" == "1" ]; then for((i=0;i<4;i++)) do eval getVal $i done elif [ "$1" == "2" ]; then echo "type" else echo "none" fi } inputVal 1 # 1 is a param Result:
yanggang@barry$ ./param.sh
0
1
2
3
===================================================
awk
#! /bin/bash # 统计type类型文件，总共含有多少行 type="*.h *.cpp" result="result.txt" # 统计函数 function cal_lines() { rm -f $result #删除文件 for file in `ls $type`; do wc -l $file >> $result #新建并追加统计行数到文件 done awk '{total+=$1} END {print total}' $result >> $result #awk累加第一列，相加结果为total } cal_lines #调用函数 cat $result #查看结果
Result:
[work]$ sh cal_lines.sh
ls: *.h: No such file or directory
91 test_performance_server.cpp
178 test_performance_ubclient1.cpp
230 test_performance_ubclient2_common_async.cpp
204 test_performance_ubclient2_common_block.cpp
206 test_performance_ubclient2_common_nonblock.cpp
191 test_performance_ubclient2_common_single_block.cpp
193 test_performance_ubclient2_common_single_nonblock.cpp
237 test_performance_ubclient2_nshead_async.cpp
220 test_performance_ubclient2_nshead_block.cpp
218 test_performance_ubclient2_nshead_nonblock.cpp
192 test_performance_ubclient2_nshead_single_block.cpp
192 test_performance_ubclient2_nshead_single_nonblock.cpp
2352
===================================================
linux实现两个文件内容相加（3种解法）
a.txt（10行） b.txt（9行）
a.txt
b.txt
解法一
awk 'NR==FNR{a[NR]=$1; b[NR]=$2} NR > FNR{print $1 + a[FNR], $2+b[FNR]}' a.txt b.txt
运行结果：
[work]$ sh cal_ab1.sh
1 83
1 77
0 128
24 195
1 130
68 227
5 132
197 233
9 146
--------------------------------------------------------------------------------------
解法二
paste a.txt b.txt > c.txt while read a b c d; do echo $((a+c)) $((b+d)) done < c.txt
运行结果：
[work]$ sh cal_ab2.sh
1 83
1 77
0 128
24 195
1 130
68 227
5 132
197 233
9 146
0 8
--------------------------------------------------------------------------------------
解法三
paste a.txt b.txt | awk '{print $1+$3 "/t" $2+$4}'
运行结果：
[work]$ sh cal_ab3.sh
1 83
1 77
0 128
24 195
1 130
68 227
5 132
197 233
9 146
0 8
--------------------------------------------------------------------------------------
评析：
解法一，结果不准确，只输出了前9行
解法二，结果正确，但不够简洁
解法三，结果正确，简洁
===================================================
while循环
# !/bin/sh TOP_NUM=800 index=0 function url_down(){ while [ $index -le $TOP_NUM ] do echo $index index=`expr $index + 24` done } url_down
运行结果：
yanggang@barry$ ./tmp.sh
0
24
48
72
96
120
144
168
192
216
240
264
288
312
336
360
384
408
432
456
480
504
528
552
576
600
624
648
672
696
720
744
768
792
-------------------------------------------------------------------------------
