awk filename not fount

1cpuer

# awk 'BEGIN{printf "filename:" FILENAME "\n"}{print $0}' c
filename:
a 12 NF
b 23 NR
c 34 FNR

关阴月飞

BEGIN {action} : 读取文本之前进行的操作。文件都没有读取，哪来的FILENAME呢？

1cpuer

回复 2# 关阴月飞

# awk '{printf "filename:" FILENAME"\n"}' c
filename:c
filename:c
filename:c
filename:c


# awk 'BEGIN{print "-no-"FILENAME}{print "nf:"NF,"nr:"NR,$0}END{print "file--"FILENAME}' c
-no-
nf:3 nr:1 a 12 NF
nf:3 nr:2 b 23 NR
nf:3 nr:3 c 34 FNR
nf:0 nr:4
file--c