Check if first character is a number with awk

Question

How to check if the first character of a string is a number using awk. I tried below but I keep getting syntax error.

awk ' { if (substr($1,1,1) == [0-9] ) print $0 }' da.txt

+3

user3437245 05 Aug 15 at 11:49

2 answers

I would use regex instead substr()

. This will do the trick:

awk '$1 ~ /^[[:digit:]]/' da.txt

Note that I am omitting print $0

as this is the default action in awk

.

+6

hek2mgl 05 Aug 15 at 11:50

sat · Accepted Answer · 2015-08-05T12:01:24+0000

I suggest using @ hek2mgl's solution. I have pointed out some of the problems.

Problems:

Really:

awk '{ if (substr($1,1,1) ~ /^[0-9]/ ) print $0 }' file.txt