fdf

    ============shell 参数传递======================
P2
[soflib@localhost ~]$ cat args
echo $# arguments passed
echo arg 1=:$1,arg 2=:$2,arg 3=:$3
[soflib@localhost ~]$ ./args a b c
3 arguments passed
arg 1=:a,arg 2=:b,arg 3=:c
[soflib@localhost ~]$ ./args x*
1 arguments passed
arg 1=:x*,arg 2=:,arg 3=:
[soflib@localhost ~]$

p3
[soflib@localhost ~]$ cat arg2
echo $# arguments passed
echo they are:$*:
[soflib@localhost ~]$ ./arg2 a b c
3 arguments passed
they are:a b c:
[soflib@localhost ~]$

p4
[soflib@localhost ~]$ cat m1.c
main(){
printf("Begin/n");
}
[soflib@localhost ~]$ vi m2.c
[soflib@localhost ~]$ cat m2.c
#include  <stdio.h>
main(){
prinf("ok!/n");
}
[soflib@localhost ~]$ vi biao
[soflib@localhost ~]$ cat biao
cat $1 $2 |wc -l
[soflib@localhost ~]$ chmod +x biao
[soflib@localhost ~]$ ./biao m1.c m2.c
7
[soflib@localhost ~]$


第8章 判断

p4
[root@localhost ~]# cat on
user="$1"
if who|grep "^user" >print
then
    echo "$user is logged on"
fi
[root@localhost ~]# vi on
[root@localhost ~]# ./on root
root is logged on
[root@localhost ~]# cat print
root     tty1         2010-04-15 14:38 (:0)
root     pts/0        2010-04-15 14:46 (:0.0)
[root@localhost ~]# pwd
/root
[root@localhost ~]#

p8 比较
[root@localhost ~]# x1="005"
[root@localhost ~]# [ "$x1"=5 ]
[root@localhost ~]# echo $?
0
[root@localhost ~]# [ "$x1" -eq 5 ]
[root@localhost ~]# echo $?
0
[root@localhost ~]#

p10   对表达式求反
[root@localhost ~]# [ ! -f "$mailfile" ]
[root@localhost ~]# echo $?
0
[root@localhost ~]# echo $x
5
[root@localhost ~]# [ !"$x"="$2" ]
bash: !"$x"="$2": event not found
[root@localhost ~]# [ ! "$x"="$2" ]
[root@localhost ~]# echo $?
1
[root@localhost ~]# [ "$x" != "$2" ]
[root@localhost ~]# echo $?
0