制表符分隔的 awk 值

如何从 TAB 分隔的字符串中选择第一列？

# echo "LOAD_SETTLED    LOAD_INIT       2011-01-13 03:50:01" | awk -F'\t' '{print $1}'

上面的代码将返回整行代码，而不是像预期的那样只返回“ LOAD _ SETTLED”。

更新:

我需要更改制表符分隔值中的第三列。以下内容不起作用。

echo $line | awk 'BEGIN { -v var="$mycol_new" FS = "[ \t]+" } ; { print $1 $2 var $4 $5 $6 $7 $8 $9 }' >> /pdump/temp.txt

但是，如果分隔符是逗号而不是制表符，那么这种方法就可以正常工作。

echo $line | awk -v var="$mycol_new" -F'\t' '{print $1 "," $2 "," var "," $4 "," $5 "," $6 "," $7 "," $8 "," $9 "}' >> /pdump/temp.txt

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Make sure they're really tabs! In bash, you can insert a tab using C-v TAB

$ echo "LOAD_SETTLED    LOAD_INIT       2011-01-13 03:50:01" | awk -F$'\t' '{print $1}'
LOAD_SETTLED

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echo "LOAD_SETTLED    LOAD_INIT       2011-01-13 03:50:01" | awk -v var="test" 'BEGIN { FS = "[ \t]+" } ; { print $1 "\t" var "\t" $3 }'

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最佳答案

You need to set the OFS variable (output field separator) to be a tab:

echo "$line" |
awk -v var="$mycol_new" -F'\t' 'BEGIN {OFS = FS} {$3 = var; print}'

(make sure you quote the $line variable in the echo statement)

小开

Should this not work?

echo "LOAD_SETTLED    LOAD_INIT       2011-01-13 03:50:01" | awk '{print $1}'

小开

You can set the Field Separator:

... | awk 'BEGIN {FS="\t"}; {print $1}'

Excellent read:

https://docs.freebsd.org/info/gawk/gawk.info.Field_Separators.html

小开

Use:

awk -v FS='\t' -v OFS='\t' ...

Example from one of my scripts.

I use the FS and OFS variables to manipulate BIND zone files, which are tab delimited:

awk -v FS='\t' -v OFS='\t' \
-v record_type=$record_type \
-v hostname=$hostname \
-v ip_address=$ip_address '
$1==hostname && $3==record_type {$4=ip_address}
{print}
' $zone_file > $temp

This is a clean and easy to read way to do this.