Useful unix character sequences

In "unix," to monitor system calls, use strace.

In "linux," to scan for hosts in local domain:

nmap -sP 192.168.1.1-255

In "linux," to download an http file without a browser, use wget.

In "emacs" to manipulate rectangular regions, mark first corner, move to second,
Ctrl-x r k (kill) Ctrl-x r y (yank).

to view ps with the full process inheritance tree, try
ps -faux

to print strings inside a binary try:
strings < binary >

to print symbols inside a binary try:
nm < binary >

to look inside an rpm:
rpm -q -l -p < .rpm file >

In "sh," to call another program, blah, with the same arguments that were passed to the shell script:

#!/bin/sh
blah $*

#!/bin/sh
blah "$@"

which also passes arguments with embedded character sequences.

In "gcc," to show all of the macros that are defined for a given platform:

gcc -dM -E test.c

In "gas," to show macro expansion listings

gas foo.s -ahlm

to spy on officemates:

/usr/sbin/tcpdump -X -s 0 src ip_address | more
to spy on net connections machines or processes: nmap or netstat -anp

In "emacs," to enable conservative indentation, add this to your .emacs files

add-hook 'c++-mode-hook
          (function (lambda ()
                       (c-set-style "k&r")
                       (setq c-basic-offset 2)
                    )))

for more information, look at

"/usr/uns/share/emacs/19.34/lisp/cc-mode.el"

In emacs, to show last typed commands: C-h l
In "gcc," stringification :

#define WARN_IF(EXP) \
do { if (EXP) \
fprintf (stderr, "Warning: " #EXP "\n"); }
while (0)

In "emacs," to create a macro : Ctrl-X "(" keys Ctrl-X ")" Ctrl-X "(" keys Ctrl-X ")"

In "emacs," to run the macro :

Ctrl-X e

In "emacs," to create a .emacs entry corresponding to a key sequence :

see emacs faq, #116

In "make," to run a command without having it barf on error :

rule:

-mkdir blah

In "gmake," fancy automatic variables.

%.s: %.S
$(RGCC) -E $< -o $@

%.lnk: %.o
$(GEO) link 0 16 0 $^ libarch.a -o $@

To use CVS over ssh:

setenv CVS_RSH ssh
alias cvs cvs -d :ext:user_name@host:cvsroot_path

When your terminal gets fucked because you tried to print out binary stuff, type "reset"
ps, so that more does not get screwed up: ps -www -aux | more
To capture screen in X.

         xwd > blah.
         xpr blah > blah.ps
        use xv to convert to ppm or whatever

To sync up the times when make sucks.
rdate < time server >
To highlight a zephyr message, hold down shift.
OpenPBS commands

qsub -V -I -q short -l nodes=1:dual2.2GHz (interactive, dual 2.2 GHz)
pbsnodes -a (list servers)
qstat -Q (list queues)
qsub -1 node=foo

To view x resources: editres

To check for non-updated files with cvs:
bash -c "cvs status 2> /dev/null | grep Status | grep Need"

To get the time on unix systems:
#include < stdio.h>
#include < stdlib.h>
#include < dlfcn.h>
#include < sys/time.h>
#include < unistd.h>

typedef unsigned long long UInt64;

UInt64 current_microseconds()
{
struct timeval tv;
struct timezone tz;

gettimeofday(&tv,&tz);
return (tv.tv_sec*1000000 + tv.tv_usec);
}

On x86-linux machines, there's a macro that accesses the
machine's cycle counter. It's higher resolution but not as portable.
You also have need to know the frequency of the machine.

#include < asm/msr.h >
{
UInt64 time;
rdtscll(time);
printf("%llu cycles\n",time);
}