bash 获取某个单词后的子串

Get a substring after a certain word

提问by Dennis

The string looks as follows:

该字符串如下所示：

Event Id: 971
Time    : Fri Mar 28 03:50:03 2014
Type    : INFO
User    : ehwe
Message :
        Oracle_Connector_1,0: Number of rows fetched on the current node: 0.

I need to get the sub string that follows the Message :. So I in this case I need this Oracle_Connector_1,0: Number of rows fetched on the current node: 0.

我需要获取Message :后面的子字符串。所以在这种情况下我需要这个 Oracle_Connector_1,0: Number of rows fetched on the current node: 0。

I've tried using b=${a%'Message :'*}format but that didn't help.

我试过使用 b=${a%'Message :'*}格式，但这没有帮助。

Little help, please?

有点帮助好吗？

Update:

更新：

Some log entries might look like the next one:

一些日志条目可能如下所示：

Event Id: 970
Time    : Fri Mar 28 03:50:03 2014
Type    : FATAL
User    : ehwe
Message :
    Oracle_Connector_1,0: [IIS-CONN-ORA-001003] The OCI function OCIStmtExecute returned status -1. Error code: 6,550, Error message: ORA-06550: line 2, column 14:
    PLS-00201: identifier 'IT' must be declared
    ORA-06550: line 2, column 14:
    PL/SQL: Item ignored
    ORA-06550: line 5, column 5:
    PLS-00320: the declaration of the type of this expression is incomplete or malformed
    ORA-06550: line 5, column 5:
    PL/SQL: Statement ignored
    ORA-06550: line 8, column 26:
    PLS-00320: the declaration of the type of this expression is incomplete or malformed
    ORA-06550: line 8, column 7:
    PL/SQL: Statement ignored. (CC_OraStatement::executePlSql, file CC_OraStatement.cpp, line 2,746)

采纳答案by fedorqui 'SO stop harming'

You can use this:

你可以使用这个：

awk 'f; /Message/ {f=1}' file

• If the flag fis set, condition is true so awkprints the line.
• Whenever the text Messageappears, the flag fis set to 1.

• 如果f设置了标志，则条件为真，因此awk打印该行。
• 每当文本Message出现时，标志f设置为 1。

---

---

Update

更新

If you want to print exactly the line after Messageoccurs, you can do:

如果要在Message发生后准确打印该行，可以执行以下操作：

$ awk 'f {print; exit} /Message/ {f=1}' file
    Oracle_Connector_1,0: [IIS-CONN-ORA-001003] The OCI function OCIStmtExecute returned status -1. Error code: 6,550, Error message: ORA-06550: line 2, column 14:

It is the same as above, just that after printing for the first time, it stops reading the file and exits.

和上面一样，只是第一次打印后停止读取文件和exits.

To use a variable as input instead of a file, use:

要使用变量而不是文件作为输入，请使用：

awk 'f {print; exit} /Message/ {f=1}' <<< "$var"

See an example:

看一个例子：

$ echo "$var"
hello
how are you

$ awk '1' <<< "$var"
hello
how are you

回答by Aslan

grep -A1 Message | tail -1should do the trick. -A1 tells grep the write one more line to the output (after 1) when a match is found.

grep -A1 Message | tail -1应该做的伎俩。-A1 告诉 grep 在找到匹配项时再向输出写入一行（在 1 之后）。

回答by Henk Langeveld

I expect ${a%'Message :'*}to return the firstfour lines. If $acontains the entire message above, reverse the match:

我希望${a%'Message :'*}返回前四行。如果$a包含上面的整个消息，则反转匹配：

a="Event Id: 971
Time    : Fri Mar 28 03:50:03 2014
Type    : INFO
User    : ehwe
Message :
        Oracle_Connector_1,0: Number of rows fetched on the current node: 0."

echo "${a#*Message :[$IFS]}"

Outputs:

输出：

        Oracle_Connector_1,0: Number of rows fetched on the current node: 0.

Note: Using [$IFS]because I'm too lazy to figure out an explicit match with the newline character. That can be improved.

注意：使用[$IFS]是因为我懒得找出与换行符的显式匹配。这是可以改进的。

Tested in bashand ksh93

测试在bash和ksh93