Linux 如何从 awk 中的变量中修剪空白？
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How can I trim white space from a variable in awk?
提问by Hoa
Suppose $2 is my variable. I have tried going from
假设 $2 是我的变量。我试过从
awk -F\, '{print ":"}'
to
到
awk -F\, '{print gsub(/[ \t]+$/, "", ) ":"}'
But it goes from printing something to printing nothing at all.
但它从打印一些东西到什么都不打印。
采纳答案by je4d
You're printing the result of the gsub, but gsubdoes an in-place modify of $2instead of returning a modified copy. Call gsub, then print:
您正在打印 的结果gsub，但gsub会进行就地修改，$2而不是返回修改后的副本。调用gsub，然后打印：
awk -F\, '{gsub(/[ \t]+$/, "", ); print ":"}'
回答by JGC
(I don't have enough points to comment on the previous answer directly.)
（我没有足够的分数直接评论上一个答案。）
To trim whitespace at the endof $2use:
在使用结束时修剪空格$2：
awk -F\, '{gsub(/[ \t]+$/, "", ); print ":"}'
To trim whitespace at the beginningof $2use:
要在修剪空白开始的$2使用：
awk -F\, '{gsub(/^[ \t]+/, "", ); print ":"}'
And for both end and beginning:
对于结束和开始：
awk -F\, '{gsub(/^[ \t]+/, "", ); gsub(/[ \t]+$/, "", ); print ":"}'
回答by Jong Bor Lee
These functions come in handy to improve readability. They also return the trimmed result:
这些功能可以派上用场，以提高可读性。他们还返回修剪后的结果：
function ltrim(s) { sub(/^[ \t\r\n]+/, "", s); return s }
function rtrim(s) { sub(/[ \t\r\n]+$/, "", s); return s }
function trim(s) { return rtrim(ltrim(s)); }
BEGIN {
# whatever
}
{
# whatever
}
END {
# whatever
}
回答by Ben
A one liner for gawk:
Gawk 的单衬：
gawk -F\, '{ = gensub(/^[ \t]*|[ \t]*$/,"","g",)}'
回答by VIPIN KUMAR
ltrim and rtrim in Unix
Unix 中的 ltrim 和 rtrim
awk 'BEGIN{FS=OFS="|"} {gsub(/^[ \t]+|[ \t]+$/, "", $2)}1' filename.txt
awk 'BEGIN{FS=OFS="|"} {gsub(/^[ \t]+|[ \t]+$/, "", $2)}1' filename.txt
回答by DAVID ALEJANDRO PINEDA
A more simple option:
一个更简单的选择：
You have to define the trim function, the use gsub for a general replacement. Then find with a regex if starts or ends with space(one or more times), returns the field.
您必须定义修剪功能，使用 gsub 进行一般替换。如果以空格开头或结尾（一次或多次），则使用正则表达式查找，返回该字段。
awk -F'|' 'function trim(field){
gsub(/^ +| +$/,"", field);
return field
}{
OFS=",";
print trim(),trim()}' stations > lista.csv
With this code is enougth
有了这个代码就够了
And the file stationsis with this structure:
文件站具有以下结构：
1 | UTAR | U de Tarapacá
3 | VALN | Valparaíso
4 | JRGN | Junta Gorgino
6 | TRPD | Torpederas
