awk + printf 配合使用，快速格式化输出字符串

最新推荐文章于 2025-07-30 23:43:23 发布

原创最新推荐文章于 2025-07-30 23:43:23 发布 · 9.3k 阅读

2 ·

CC 4.0 BY-SA版权

文章标签：

#awk #printf #linux #文本处理

Linux/Unix学习专栏收录该内容

17 篇文章

订阅专栏

本文介绍了如何利用awk和printf在Linux环境中对文本进行格式化输出，包括从postgresql的kwlist.h文件中获取数据，根据保留关键字属性排序，并进行左对齐或右对齐的显示。

当前工作中经常遇到需要格式化输出字符串的场景，今天整理下使用awk + printf快速实现的方法。

1.数据源

选取postgresql代码库中kwlist.h文件（记录PG中保留关键字和非保留关键字信息）中的一部分作为源数据。

[root@localhost Postgres]# cat kwlist.h | grep -E '^PG_KEYWORD' | head -n 20 > source_data.txt
[root@localhost Postgres]# cat source_data.txt
PG_KEYWORD("abort", ABORT_P, UNRESERVED_KEYWORD)
PG_KEYWORD("absolute", ABSOLUTE_P, UNRESERVED_KEYWORD)
PG_KEYWORD("access", ACCESS, UNRESERVED_KEYWORD)
PG_KEYWORD("action", ACTION, UNRESERVED_KEYWORD)
PG_KEYWORD("add", ADD_P, UNRESERVED_KEYWORD)
PG_KEYWORD("admin", ADMIN, UNRESERVED_KEYWORD)
PG_KEYWORD("after", AFTER, UNRESERVED_KEYWORD)
PG_KEYWORD("aggregate", AGGREGATE, UNRESERVED_KEYWORD)
PG_KEYWORD("all", ALL, RESERVED_KEYWORD)
PG_KEYWORD("also", ALSO, UNRESERVED_KEYWORD)
PG_KEYWORD("alter", ALTER, UNRESERVED_KEYWORD)
PG_KEYWORD("always", ALWAYS, UNRESERVED_KEYWORD)
PG_KEYWORD("analyse", ANALYSE, RESERVED_KEYWORD)        /* British spelling */
PG_KEYWORD("analyze", ANALYZE, RESERVED_KEYWORD)
PG_KEYWORD("and", AND, RESERVED_KEYWORD)
PG_KEYWORD("any", ANY, RESERVED_KEYWORD)
PG_KEYWORD("array", ARRAY, RESERVED_KEYWORD)
PG_KEYWORD("as", AS, RESERVED_KEYWORD)
PG_KEYWORD("asc", ASC, RESERVED_KEYWORD)
PG_KEYWORD("assertion", ASSERTION, UNRESERVED_KEYWORD)

2.将关键字按照保留或非保留的属性排序输出

[root@localhost Postgres]# cat source_data.txt | awk -F ",|)" '{print $3 "," $2}' | tr -d ' ' | sort
RESERVED_KEYWORD,ALL
RESERVED_KEYWORD,ANALYSE
RESERVED_KEYWORD,ANALYZE
RESERVED_KEYWORD,AND
RESERVED_KEYWORD,ANY
RESERVED_KEYWORD,ARRAY
RESERVED_KEYWORD,AS
RESERVED_KEYWORD,ASC
UNRESERVED_KEYWORD,ABORT_P
UNRESERVED_KEYWORD,ABSOLUTE_P
UNRESERVED_KEYWORD,ACCESS
UNRESERVED_KEYWORD,ACTION
UNRESERVED_KEYWORD,ADD_P
UNRESERVED_KEYWORD,ADMIN
UNRESERVED_KEYWORD,AFTER
UNRESERVED_KEYWORD,AGGREGATE
UNRESERVED_KEYWORD,ALSO
UNRESERVED_KEYWORD,ALTER
UNRESERVED_KEYWORD,ALWAYS
UNRESERVED_KEYWORD,ASSERTIO

3.将关键字按照保留或非保留的属性排序，并按照左对齐／右对齐输出

[root@localhost Postgres]# cat source_data.txt | awk -F ",|)" '{print $3 "," $2}' | tr -d ' ' | sort | awk -F "," '{printf "%-20s,%12s\n",$1,$2}'
RESERVED_KEYWORD    ,         ALL
RESERVED_KEYWORD    ,     ANALYSE
RESERVED_KEYWORD    ,     ANALYZE
RESERVED_KEYWORD    ,         AND
RESERVED_KEYWORD    ,         ANY
RESERVED_KEYWORD    ,       ARRAY
RESERVED_KEYWORD    ,          AS
RESERVED_KEYWORD    ,         ASC
UNRESERVED_KEYWORD  ,     ABORT_P
UNRESERVED_KEYWORD  ,  ABSOLUTE_P
UNRESERVED_KEYWORD  ,      ACCESS
UNRESERVED_KEYWORD  ,      ACTION
UNRESERVED_KEYWORD  ,       ADD_P
UNRESERVED_KEYWORD  ,       ADMIN
UNRESERVED_KEYWORD  ,       AFTER
UNRESERVED_KEYWORD  ,   AGGREGATE
UNRESERVED_KEYWORD  ,        ALSO
UNRESERVED_KEYWORD  ,       ALTER
UNRESERVED_KEYWORD  ,      ALWAYS
UNRESERVED_KEYWORD  ,   ASSERTION

这里只记录了通过awk + printf实现简单的格式化输出的方法，awk是强大的文本处理工具，在后续实践中不断完善次文档。