Awk和Grep的问题

Question

我喜欢从wmctrl获取window pid(只有firefox),我试过wmctrl -lp | grep Firefox | awk -F"""{print $ 1}"但输出与我的预期不符.请帮忙.

beer@beer-laptop# wmctrl -lp
0x0160001b -1 6504   beer-laptop x-nautilus-desktop
0x016000bd  0 6504   beer-laptop conference - File Browser
0x03e00003  0 0              N/A XBMC Media Center
0x03800081  0 7282   beer-laptop Xbmc_ConferenceWindow.py (~/.qlive/xbmc-conference) - gedit
0x0352f117  0 6963   beer-laptop Ask a Question - Stack Overflow - Chromium
0x01400040 -1 6503   beer-laptop Top Expanded Edge Panel
0x01400003 -1 6503   beer-laptop Bottom Expanded Edge Panel
0x03202deb  0 6866   beer-laptop beer@beer-laptop: ~/.qlive/conference
0x012000c4  0 12134  beer-laptop Common threads: Awk by example, Part 1 - Mozilla Firefox
beer@beer-laptop# wmctrl -lp | grep Firefox | awk -F"  " "{print $1}"
0x012000c4  0 12134  beer-laptop Common threads: Awk by example, Part 1 - Mozilla Firefox

• 在这种情况下,我更喜欢= 0x012000c4

Answer 1

wmctrl -lp | awk '/Firefox/ { print $1 }'

不需要grep.Awk会这样做.默认字段分隔符也是空格,因此无需指定.另外,在awk脚本周围使用单引号,这样shell就不会扩展$ 1.这就是你的脚本失败的原因.$ 1变成了什么,你的awk动作变成了"print",打印出整条线.