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If the 'lm' flag is present, then the CPU is 64-bit.
If no output, then CPU is 32-bit.
From 'man netstat'
"netstat -i | -I interface [-abdnt] [-f address_family] [-M core] [-N system]
Show the state of all network interfaces or a single interface
which have been auto-configured (interfaces statically configured
into a system, but not located at boot time are not shown). An
asterisk (``*'') after an interface name indicates that the
interface is ``down''. If -a is also present, multicast
addresses currently in use are shown for each Ethernet interface
and for each IP interface address. Multicast addresses are shown
on separate lines following the interface address with which they
are associated. If -b is also present, show the number of bytes
in and out. If -d is also present, show the number of dropped
packets. If -t is also present, show the contents of watchdog
This is a nice way to kill processes.. the example here is for firefox!!! substitute firefox for whatever the process name is...
To save the result, redirect the output to another file.
grep -v "^$" file1 > file2
Useful to check DDoS attacks on servers.
Yet another ps grep function, but this one includes the column headings.
My variant on this common function. Some highlights:
Allows you to override the default ps args of "aux"
Uses bracket trick to omit the grep process itself without having to use a second grep
Always prints the correct header row of ps output
Limitations: Ugly ps error output if you forget to quote your multi word grep argument
This command takes the output of the 'last' command, removes empty lines, gets just the first field ($USERNAME), sort the $USERNAMES in reverse order and then gives a summary count of unique matches.
Searching for a String in Multiple Files With Grep
This will give you the Dell Service tag number associated with your machine. Incredibly useful when you need that number for tech support or downloads.
This command deletes all files in all subfolders if their name or path contains "deleteme".
To dry-run the command without actually deleting files run:
find . | grep deleteme | while read line; do echo rm $line; done
This is a 'killall' command equivalent where it is not available.
Prior to executing it, set the environment variable USERNAME to the username, whose processes you want to kill or replace the username with the $USERNAME on the command above.
Side effect: If any processes from other users, are running with a parameter of $USERNAME, they will be killed as well (assuming you are running this as root user)
[-9] in square brackets at the end of the command is optional and strongly suggested to be your last resort. I do not like to use it as the killed process leaves a lot of mess behind.
finds all forms instanciated into a symfony project, pruning svn files.
Get simple description on each file from /bin dir, in list form, usefull for newbies.
this will find text in the directory you specify and give you line where it appears.
/proc/cpuinfo contains information about the CPU.
Search for "processor" in the /proc/cpuinfo file
wc -l, counts the number of lines.
grep -sq "" filename && command
grep can be used in combination with && to run a command if a file exists.
The trick here is to use the brackets [ ] around any one of the characters of the grep string. This uses the fact that [?] is a character class of one letter and will be removed when parsed by the shell. This is useful when you want to parse the output of grep or use the return value in an if-statement without having its own process causing it to erroneously return TRUE.
Filter comments and empty lines in files. I find this very useful when trying to find what values are actually set in a very long example config file.
I often set an alias for it, like :
alias nocomment='grep -v "^\($\|#\)"'
only works for freeBSD where ports are installed in /usr/ports
credit to http://wiki.freebsd.org/PortsTasks
changes the PS1 to something better than default.
[username.hostname.last-2-digits-of-ip] (current directory)
Very useful set of commands to know when your file system was created.