在读ABS(Advanced Bash-Scripting Guide)的时候，遇到书中的示例代码如下:
1 #!/bin/bash
2 # broken-link.sh
3 # Written by Lee bigelow >ligelowbee@yahoo.com< 4 # Used with permission.
5
6 #A pure shell script to find dead symlinks and output them quoted
7 #so they can be fed to xargs and dealt with
8 #eg. broken-link.sh /somedir /someotherdir|xargs rm
9 #
10 #This, however, is a better method:
11 #
12 #find “somedir” -type l -print0|\
13 #xargs -r0 file|\
14 #grep “broken symbolic”|
15 #sed -e ‘s/^|: broken symbolic.$/“/g’
16 #
17 #but that wouldn’t be pure bash, now would it.
18 #Caution: beware the /proc file system and any circular links!
19 ###################################
20
21
22 #If no args are passed to the script set directorys to search
23 #to current directory. Otherwise set the directorys to search
24 #to the agrs passed.
25 ####################
26 [ $# -eq 0 ] && directorys=pwd || directorys=$@
27
28 #Setup the function linkchk to check the directory it is passed
29 #for files that are links and don’t exist, then print them quoted.
30 #If one of the elements in the directory is a subdirectory then
31 #send that send that subdirectory to the linkcheck function.
32 ##########
33 linkchk () {
34 for element in $1/*; do
35 [ -h “$element” -a ! -e “$element” ] && echo \”$element\”
36 [ -d “$element” ] && linkchk $element
37 # Of course, ‘-h’ tests for symbolic link, ‘-d’ for directory.
38 done
39 }
40
41 #Send each arg that was passed to the script to the linkchk function
42 #if it is a valid directoy. If not, then print the error message
43 #and usage info.
44 ################
45 for directory in $directorys; do
46 if [ -d $directory ]
47 then linkchk $directory
48 else
49 echo “$directory is not a directory”
50 echo “Usage: $0 dir1 dir2 …”
51 fi
52 done
53
54 exit 0
想复制下来自己执行一下，无奈每行都有行号，不能直接做为shell脚本执行，当然不甘心了，于是想到强大的awk，写了如下awk脚本:
{
i=2;
while (i >= NF) {
ORS=” “;
if (i == NF) {
ORS=”\n”;
}
print $i;
i++;}
}
其实很简单，只要实现不打印第一个字段的内容，就可以完成消除行号。似乎应该有更简单的awk脚本，更是暂时没有想到,所以用了这个笨办法，从第二个字段开始打印，直到NF(当前记录的字段总数)，默认的print打印字段后是输出一个“\n”,于是做了一个简单的判定，只有当打印最后一个字段后才输出”\n”,否则使用” “(空格)作为print的额外输出。
不知道哪位对awk比较熟悉，如何能使这个脚本更简单(用一行语句就搞定),麻烦告诉我一声
同样,这个脚本可以处理使用”cat -n”(该命令作用是给每一行加行号) 命令生成的文件
有关awk的参考文章:FROM
Comments
cocobear: sed正则不错。
ninesuns: sed -s ‘s/^[0-9]\{1,\}//‘ filename
