awk参数解析

Posted 2020-12-03 carriezhangyan

# awk --help
Usage: awk [POSIX or GNU style options] -f progfile [--] file ...
Usage: awk [POSIX or GNU style options] [--] ‘program‘ file ...
POSIX options:          GNU long options: (standard)
        -f progfile             --file=progfile
        -F fs                   --field-separator=fs
        -v var=val              --assign=var=val
Short options:          GNU long options: (extensions)
        -b                      --characters-as-bytes
        -c                      --traditional
        -C                      --copyright
        -d[file]                --dump-variables[=file]
        -e ‘program-text‘       --source=‘program-text‘
        -E file                 --exec=file
        -g                      --gen-pot
        -h                      --help
        -L [fatal]              --lint[=fatal]
        -n                      --non-decimal-data
        -N                      --use-lc-numeric
        -O                      --optimize
        -p[file]                --profile[=file]
        -P                      --posix
        -r                      --re-interval
        -S                      --sandbox
        -t                      --lint-old
        -V                      --version

To report bugs, see node `Bugs‘ in `gawk.info‘, which is
section `Reporting Problems and Bugs‘ in the printed version.

gawk is a pattern scanning and processing language.
By default it reads standard input and writes standard output.

Examples:
        gawk ‘{ sum += $1 }; END { print sum }‘ file
        gawk -F: ‘{ print $1 }‘ /etc/passwd

 

awk -F[分隔符] ‘/搜索的字符串/{print $0}’

awk 命令不加-F选项，默认分隔符是空格

例如：搜索系统空间使用的大小：

# df -h
Filesystem      Size  Used Avail Use% Mounted on
devtmpfs        3.9G     0  3.9G   0% /dev
tmpfs           3.9G  4.0K  3.9G   1% /dev/shm
tmpfs           3.9G  1.2M  3.9G   1% /run
tmpfs           3.9G     0  3.9G   0% /sys/fs/cgroup
/dev/sda2       9.8G  6.7G  2.6G  73% /
/dev/sda3       209G  353M  198G   1% /data

1、搜索系统根目录使用的空间大小

    #df -h |awk ‘/sda2/{print $4}‘  

2、提取系统使用空间的整数部分

    #df -h |awk ‘/sda2/{print $4}‘ |awk -F[.G] ‘{print $1}‘

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