awk使用ARGC和ARGV來在命令行中傳入一些變量到awk腳本中。其中:
- ARGC包含傳入awk腳本的參數的總數目
- ARGV爲一個包含所有傳入awk腳本的參數的數組,該數組下標從0到ARGC-1。
- 當你傳入5個參數,ARGC的值爲6
- ARGV[0]總是"awk"
fengxi@ubuntu:~/bash/awk$ cat arguments.awk
BEGIN {
print "ARGC=", ARGC
for(i=0;i<ARGC;i++)
print ARGV[i]
}
fengxi@ubuntu:~/bash/awk$ awk -f arguments.awk arg1 arg2
ARGC= 3
awk
arg1
arg2
在gawk中,當前正在處理的文件是存儲在ARGV數組中,該數組可在循環塊中被訪問。ARGIND是訪問ARGV數組的下標去檢索當前文件。當你在awk腳本中僅僅處理一個文件時,ARGIND的值爲1,並且ARGV[ARGIND]會返回當前正在處理的文件名。{
print "ARGIND:", ARGIND
print "Current file:", ARGV[ARGIND]
}
fengxi@ubuntu:~/bash/awk$ awk -f argind.awk num.txt
ARGIND: 1
Current file: num.txt
ARGIND: 1
Current file: num.txt
ARGIND: 1
Current file: num.txt
ARGIND: 1
Current file: num.txt
ARGIND: 1
Current file: num.txt
其中num.txt的內容爲:fengxi@ubuntu:~/bash/awk$ cat num.txt
1
2
3
4
5
如果傳入不是一個文件,而是兩個文件,則輸出結果爲:fengxi@ubuntu:~/bash/awk$ awk -f argind.awk num.txt num2.txt
ARGIND: 1
Current file: num.txt
ARGIND: 1
Current file: num.txt
ARGIND: 1
Current file: num.txt
ARGIND: 1
Current file: num.txt
ARGIND: 1
Current file: num.txt
ARGIND: 2
Current file: num2.txt
ARGIND: 2
Current file: num2.txt
num2.txt的內容爲:fengxi@ubuntu:~/bash/awk$ cat num2.txt
1
2