ps -u username #list all processing started by username kill pic # terminate process pmap pid           #show process's memory mapping/usage   ls -l  directory  # list all files in directory grep keyword  filename   #search keyword in file fgrep egrep   find directory -name filename   #search filename in directory   less # look into file content shift+G: jump to end, shift+P: jump to begin, shift+F: keep appending   chmod #change file privilege: r,w, x cp, rm -r, rmdir, mkdir   cat, cut, tr, sed #editing format file   gzip # compress tool tar   vi file #edit file content   #subversion svn up #update working directory svn co #check out svn diff -r 145:144 #compare two versions svn status #show working dirctory's status svn info svn log -r versionNum     make   hostname