How to remove the plus sign after the Linux Kernel version number

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The kernel version number is generated based on the numbers provided in Makefile. Open Makefile, and the file begins to see:

1 VERSION = 3

2 PATCHLEVEL = 10

3 SUBLEVEL = 28

4 EXTRAVERSION =

5 NAME = TOSSUG Baby Fish

The file related to kernel version number generation is scripts/setlocalversion, which contains the following partial scripts:

# scm version string if not at a tagged commit

If test "$CONFIG_LOCALVERSION_AUTO" = "y"; then

# full scm version string

Res= "$res$ (scm_version)"

Else

# append a plus sign if the repository is not in a clean

# annotated or signed tagged state (as git describe only

# looks at signed or annotated tags-git tag-a Universe) and

# LOCALVERSION= is not specified

If test "${LOCALVERSION+set}"! = "set"; then

Scm=$ (scm_version-- short)

Res= "$res$ {scm:++}"

Fi

Fi

If

CONFIG_LOCALVERSION_AUTO

It is not configured, and LOCALVERSION has no values, so, according to the above script, the + sign will not be added.

When you actually compile the code, you can execute:

LOCALVERSION= make

In addition, in the file scripts/setlocalversion, there is a sentence:

If test-d. Git & & head= `git rev-parse-- verify-- short HEAD 2 "/ dev/ null`

Git rev-parse is used to retrieve the id of the most recent commit:

$git rev-parse-verify-short HEAD

E77fcc1

Charles@taotao:~/code/linux-3.10.28$ git rev-parse-- verify HEAD

E77fcc1e9be7a0ab373f96d5b9d58e1136c8c4b0

Or use:

$git log-- pretty=format:'%h'-n 1

E77fcc1

${LOCALVERSION+set} is variable expansion modfier.

It comes in several forms:

${variable:-word} if variable is set to a value that is not empty, then the value of this expression is the value of variable; otherwise, it is the value of word (the value of variable remains the same)

${variable:=word} if variale is set or the value is not empty, then the value of this expression is the value of variable; otherwise, it is the value of word (the value of variable is updated)

${variable:+word} if variable is set to a value that is not empty, then the value of this expression is the value of variable; otherwise, it is NULL.

${variable:offset} gets a substring of the string (since the variable string index is offset, the offset value is calculated from 0)

${variable:? Word} if variable is set to a value that is not empty, then the value of this expression is the value of variable; otherwise, print the value of word and exit.

${variable:offset:length} get the string of variable (starting with offset, the length is length)

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