如果要持續(xù)執(zhí)行一個(gè)命令，然后觀察輸出的話，我們一遍一遍的按上回車，然后看著輸出。watch命令可以很好的實(shí)現(xiàn)這個(gè)功能。比如，要監(jiān)控linux的連接數(shù)：
- watch -n 2 -d 'netstat -est | grep est'
輸出：
- Every 2.0s: netstat -est | grep est Mon Mar 19 10:46:03 2012
-
- 12784 connections established
- 556 packets rejects in established connections because of timestamp
- 2015 congestion windows fully recovered without slow start
- 9672 congestion windows partially recovered using Hoe heuristic
- 20983 congestion windows recovered without slow start by DSACK
- 22010 congestion windows recovered without slow start after partial ack
-n指定命令執(zhí)行的時(shí)間間隔，-d高亮顯示連續(xù)兩側(cè)輸出的差別，為了便于觀察，最后一個(gè)參數(shù)是要執(zhí)行的命令。