Linux Quick-Ref


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things I always forget
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config xwindows 
XF86Setup 
kernel compiling 
cd /usr/src/linux 
make xconfig     or menuconfig, config 
make clean     (cp fl.35 fl.o) 
make dep 
make zImage     or zdisk 
... 
make mrproper     deletes zImage... 
modify Kernel image 
rdev zImage /dev/fd0     set root device 
rdev -r zImage 32768 
    value = bit 0-10 Offset in 1024 bytes of ramdisk 
    bit 14 load ramdisk 
    bit 15 prompt before loading root file system 
make file system
mke2fs -m 0 /dev/fd0     create ext2 file system on floppy disk 
mount
mount -t ext2 /dev/fd0 /mnt/floppy 
umount /mnt/floppy 
loopdevice 
insmod loop.o 
dd if=/dev/fd0 of=fdisk.img     make floppy-disk image 
losetup /dev/loop0 fdisk.img     link fdisk.img to /dev/loop0 
mount -t msdos /dev/loop0 /mnt/loop     mount image 

dd if=/dev/zero of=file.img bs=1k count=360     make ext2 image 
mke2fs -m 0 file.img     create fs on it 
mount –o loop file.img /mnt/loop     mount it 
rmmod loop.o 
check dependencies 
ldd /bin/execute 
file /lib/libname     lib loader (Qmagic=a.out=ld.so, ELF=ld-linux.so) 
copy 
cp -a src1 src2 dstfiles 
cp –arv /src/* /dstdir     (recursive verbose) 
objcopy --strip-all xsrc xdest     strip xecutes 
objcopy --strip-debug lsrc ldeststripedexe 
link 
ln src hardlink     points to physical place 
ln -s src softlink     points to src path 
manpage
man cmd/fie
apropos keyword 
printing
man -t mount | lpr -Pps     manpage printing 
enscript textfile 
dir list
ls -lt     long sort by time 
ls -ltru     list last uaccess time revers order 
ps
ps x     x also shows deamons 
screendump
cat /dev/vcs1     dumps tty1 
find
find / -iname fnam*     start in / ignore case 
compressing 
gzip -v9 -c f1 f2 >file.gz     compress file f1 f2 
gzip -v9 -c f3 >>file.gz     add file f3 
gzip -l -c file.gz     -d (decompress) 
tar –tzf file.tgz     list files/dir compr file 
tar –czvf file.tgz dir/*     compress dir 
tar –xzvpf file.tgz dir     extract dir verbose 
zcat < file.tgz | star     extract 

Shell scripts (ash) 
#!/bin/sh 
. /path/take_commands_from_this_file 
cd() { command cd $@; PS1="`pwd`# "; } 
cmd >file_stdout 
cmd 2>file_stderr 
VAR=`cat /file` 
[ $VAR = 12 ] &&     only_if_true 
[ $VAR = 12 ] ||     only_if_false 
if test –x cmd; then     exec cmd 
else echo –n     cmd not executable 
fi 
for $ITEM in "A B C"; do list; done 
while exp; do list; break; continue; done 
case "AL AB CD" in 
A|B) list;; 
C?) list;; 
esac 

Linux Boot 
lilo / loadlin -> decompress & start kernel 
mount root device (decompress rootimg.gz) 
/linuxrc 
/sbin/init-> /etc/inittab -> /etc/rc.. -> getty -> login -> sh -> profile(s) 
lilo.conf 
boot=/dev/fd0 
install=/boot/boob.b 
map=/boot/map 
read-write 
compact 
prompt 
image=/zImage 
label=Linux 
root=/dev/fd0 

lilo installlilo -v -C lilo.conf -r /mnt/floppy 

loadlin.exe zImage initrd=fdroot.gz root=/dev/ram 

Linux Network config 
ifconfig lo inet 127.0.0.1 netmask 255.0.0.0 
ifconfig eth0 inet 204.204.204.13 netmask 255.255.255.0 
route add -net 127.0.0.0 netmask 255.0.0.0 dev lo 
route add -net 204.204.204.0 netmaks 255.255.255.0 dev eth0 
route add default gw 204.204.204.100 

/etc/hosts
ip.ip.ip.adr fqhostname.domain.where alias nickname 
/etc/resolf.conf
DNS1
DNS2 

Linux GCC 
compiling 
gcc –m386 –O2 –Wall –o execname src1.cc src2.cc 
-o execname (a.out)     -c compile only 
-O0 no optimalisation     -S generate asm source 
-g enable debugging     -l libname 
default file ext src.c src.cc asm.s obj.o arch.a lib.a 
debugging 
gdb execname -tty=/dev/tty8 
run arguments ctrl-c 
list fie     break 
next     step     continue     finish 
print varname     set varname=value 
backtrace     quit 
gdb execname core     (coredump) 
gproff execname gmon.out     (compile with option –pg) 
Makefile 
LDFLAGS= 
LIBRARIES= 
CC= gcc 
CFLAGS= -Wall -m386 -o2 
mySRC= src1.c src2.c 
OBJECTS= $(patsubst %.c, %.o, $(mySRC)) 
all: execname $(LINKS) 
execname: $(OBJECTS) 
$(CC) $(CFLAGS) $(LDFLAGS) -o execname $(OBJECTS) $(LIBRARIES) 
objcopy --strip -all execname execstrip 
clean: 
- rm -f $(OBJECTS) *~