值得注意的是,这里的文档也可以在bash循环中使用。此示例显示了如何获取表的列列表:
export postgres_db_name='my_db'
export table_name='my_table_name'
# start copy
while read -r c; do test -z "$c" || echo $table_name.$c , ; done < <(cat << EOF | psql -t -q -d $postgres_db_name -v table_name="${table_name:-}"
SELECT column_name
FROM information_schema.columns
WHERE 1=1
AND table_schema = 'public'
AND table_name =:'table_name' ;
EOF
)
# stop copy , now paste straight into the bash shell ...
output:
my_table_name.guid ,
my_table_name.id ,
my_table_name.level ,
my_table_name.seq ,
甚至没有换行
while read -r c; do test -z "$c" || echo $table_name.$c , | perl -ne
's/\n//gm;print' ; done < <(cat << EOF | psql -t -q -d $postgres_db_name -v table_name="${table_name:-}"
SELECT column_name
FROM information_schema.columns
WHERE 1=1
AND table_schema = 'public'
AND table_name =:'table_name' ;
EOF
)
# output: daily_issues.guid ,daily_issues.id ,daily_issues.level ,daily_issues.seq ,daily_issues.prio ,daily_issues.weight ,daily_issues.status ,daily_issues.category ,daily_issues.name ,daily_issues.description ,daily_issues.type ,daily_issues.owner
cat
。尝试psql ... << EOF ...
也请参见“这里字符串”。mywiki.wooledge.org/BashGuide/InputAndOutput?#Here_Strings