sed awk 用模式匹配替换行

Question

使用 awk 或 sed 如何在模式匹配后替换每一行？模式总是以 S:\ 和其他东西开始，我需要从 S:\~ 到末尾的整行出现在空行之前的下一行中。

我有这样的输入：

S:\dir1\subfolder1longsubf
abcdefg
1234567
permissions

S:\dir2\verylongsub
some random string
some random string

S:\dir3
some random string
some random string

S:\dir4\sub2\sub3
some random string
some random string
some random string

我需要这样的输出：

S:\dir1\subfolder1longsubf
S:\dir1\subfolder1longsubf
S:\dir1\subfolder1longsubf
S:\dir1\subfolder1longsubf

S:\dir2\verylongsub
S:\dir2\verylongsub
S:\dir2\verylongsub

S:\dir3
S:\dir3
S:\dir3

S:\dir4\sub2\sub3
S:\dir4\sub2\sub3
S:\dir4\sub2\sub3
S:\dir4\sub2\sub3

Answer 1

我会用 awk:

awk '/^S/ {line=[=10=]} {print NF?line:""}' file

这将存储以 S 开头的行。然后，如果该行为空，它会打印此存储值或空行。

测试

$ awk '/^S/ {line=[=11=]} {print NF?line:""}' file
S:\dir1\subfolder1longsubf
S:\dir1\subfolder1longsubf
S:\dir1\subfolder1longsubf
S:\dir1\subfolder1longsubf

S:\dir2\verylongsub
S:\dir2\verylongsub
S:\dir2\verylongsub

S:\dir3
S:\dir3
S:\dir3

S:\dir4\sub2\sub3
S:\dir4\sub2\sub3
S:\dir4\sub2\sub3
S:\dir4\sub2\sub3

Answer 2

使用 GNU sed：

sed  '/^S:/{h};/^[^S]/{g}' file

sed awk 用模式匹配替换行

sed awk replace lines with a pattern match

awk

replace

sed

测试