grep
教學網站
- http://www.cyberciti.biz/faq/grep-regular-expressions/
- https://www.ubuntupit.com/practical-grep-command-for-linux-enthusiasts/
文字過濾
使用 . (period) 表示一個任意字元
$ grep dev.sda /etc/fstab
/dev/sda3 / reiserfs noatime,ro 1 1
/dev/sda1 /boot reiserfs noauto,noatime,notail 1 2
/dev/sda2 swap swap sw 0 0
#/dev/sda4 /mnt/extra reiserfs noatime,rw 1 1
使用 [ ]
$ grep dev.sda[12] /etc/fstab
/dev/sda1 /boot reiserfs noauto,noatime,notail 1 2
/dev/sda2 swap swap sw 0 0
使用 [^12] 表示非1,2字元
$ grep dev.sda[^12] /etc/fstab
/dev/sda3 / reiserfs noatime,ro 1 1
#/dev/sda4 /mnt/extra reiserfs noatime,rw 1 1
使用正規表示
$ grep '^#' /etc/fstab
# /etc/fstab: static file system information.
#
$ grep '^#.*\.$' /etc/fstab
# /etc/fstab: static file system information.
#
$ grep 'foo$' filename
搜尋與關鍵字大小寫一致的行
grep -w "boo" myfile.txt
grep "\<boo\>" myfile.txt
搜尋包含特殊字元 *** 的關鍵字
grep '\*\*\*' myfile.txt
搜尋 email 地址
grep -E -o "\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,6}\b" /path/to/data
搜尋 IP 位址
egrep '\b(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)' /etc/hosts
grep -E -o "(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)" /var/log/auth.log
更多應用語法
grep '[vV][iI][Vv][Ee][kK]' filename
grep '[vV]ivek' filename
grep -w '[vV]ivek[0-9]' filename
grep 'foo[0-9][0-9]' filename
grep '[A-Za-z]' filename
grep [wn] filename
搜尋多個關鍵字(使用正規運算式)
ls /var/log/ | grep -E "http|secure"
ls /var/log/ | grep "http\|secure"
grep -Ev "^(#|;)" example.txt
檢查設定檔的參數
CONFIG_CHECK=`grep "^# SparkleShare$" /etc/ssh/sshd_config`
if ! [ "$CONFIG_CHECK" = "# SparkleShare" ]; then
echo "" >> /etc/ssh/sshd_config
echo "# SparkleShare" >> /etc/ssh/sshd_config
echo "Match User storage" >> /etc/ssh/sshd_config
echo " PasswordAuthentication no" >> /etc/ssh/sshd_config
fi
在許多檔案內尋找特定字串內容
應用:程式碼編寫及除錯
cd /var/www/html
grep -r "[搜尋關鍵字]" *
grep -Ril "specific_text" /path/to/dir
搜尋特定字串的文字段落內容
應用:檢查系統的硬體裝置,以及類似 AIX 的 grep -p
見附檔: grepp.awk