Question

我想将第二列更改为大写，我想仅在shell脚本中执行此操作。（没有人衬里！）

#!/bin/sh
# read file line by line
file="/pdump/country.000000.txt"
while read line
do
mycol=`echo $line | awk -F"," '{print $2}'`
mycol_new=`echo $mycol | tr "[:lower:]" [:upper:]`
echo $line | awk -F"," '{print $1 "," $mycol_new "," $3 "," $4 "," $5 "," $6 "," $7 "," $8}'
done < $file

我无法用$ mycol_new替换$ 2。有什么建议吗？

Answer 1

awk无法看到$mycol_new，因为它是一个shell变量。这是使用-v标志将shell变量传递给awk的一种方法：

echo $line | awk -v var="$mycol_new" -F"," '{print $1 "," var "," $3 "," $4 "," $5 "," $6 "," $7 "," $8}'

以下是另一种让shell展开$mycol_new的方法：

echo $line | awk -F"," '{print $1 ",'"$mycol_new"'," $3 "," $4 "," $5 "," $6 "," $7 "," $8}'

Answer 2

为什么没有一个衬垫？做作业？

$ cat file
one two three four
five six seven eight

$ awk '{$2=toupper($2)}1' file
one TWO three four
five SIX seven eight

Answer 3

如果你想在shell中完成所有这些，那么你不需要awk：

IFS=,
while read line; do
  set -- $line
  a="$1"
  b="${2^^}"  # assumes bash, use "tr" otherwise
  shift 2
  set -- "$a" "$b" "$@"
  echo "$*"
done < "$file" > "$file.new"

使用shell脚本替换第二列

3 个答案: