NOT DEFTERİ, BİLGİ PAYLAŞIMI TIRI VIRI…

cat exitstatus.sh
#! /bin/bash
 
echo -e "Successful execution"
echo -e "====================="
echo "hello world"
# Exit status returns 0, because the above command is a success.
echo "Exit status" $? 
 
echo -e "Incorrect usage"
echo -e "====================="
ls --option
# Incorrect usage, so exit status will be 2.
echo "Exit status" $? 
 
echo -e "Command Not found"
echo -e "====================="
bashscript
# Exit status returns 127, because bashscript command not found
echo "Exit status" $? 
 
echo -e "Command is not an executable"
echo -e "============================="
ls -l execution.sh
./execution.sh
# Exit status returns 126, because its not an executable.
echo "Exit status" $?

Nic’in özelliklerinin elde edilmesi

ethtool eth0
Settings for eth0:
        Supported ports: [ TP ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Supports auto-negotiation: Yes
        Advertised link modes:  10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Advertised auto-negotiation: Yes
        Speed: 100Mb/s
        Duplex: Full
        Port: Twisted Pair
        PHYAD: 1
        Transceiver: internal
        Auto-negotiation: on
        Supports Wake-on: d
        Wake-on: d
        Link detected: yes

Duplex değeri için 3 olasılık vardır

• Full duplex : Enables sending and receiving of packets at the same time. This mode is used when the ethernet device is connected to a switch.
• Half duplex : Enables either sending or receiving of packets at a single point of time. This mode is used when the ethernet device is connected to a hub.
• Auto-negotiation : If enabled, the ethernet device itself decides whether to use either full duplex or half duplex based on the network the ethernet device attached to.

ethtool -s ile nic özellikleri değiştirilebilir.
autoneg özelliğini değiştirelim.

ifdown eth0
    eth0      device: Broadcom Corporation NetXtreme II BCM5709 Gigabit Ethernet (rev 20)
    eth0      configuration: eth-bus-pci-0000:0b:00.0
 
ethtool  -s eth0 autoneg off
 
ethtool eth0
Settings for eth0:
        Supported ports: [ TP ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Supports auto-negotiation: Yes
        Advertised link modes:  Not reported
        Advertised auto-negotiation: No
        Speed: Unknown! (65535)
        Duplex: Unknown! (255)
        Port: Twisted Pair
        PHYAD: 1
        Transceiver: internal
        Auto-negotiation: off
        Supports Wake-on: g
        Wake-on: g
        Link detected: no
# ifup eth0

Nic’in speed değerini sabitlemek için:

ethtool -s eth0 speed 100 autoneg off
 
ethtool eth0
Settings for eth0:
        Supported ports: [ TP ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Supports auto-negotiation: Yes
        Advertised link modes:  Not reported
        Advertised auto-negotiation: No
        Speed: Unknown! (65535)
        Duplex: Unknown! (255)
        Port: Twisted Pair
        PHYAD: 1
        Transceiver: internal
        Auto-negotiation: off
        Supports Wake-on: g
        Wake-on: g
        Link detected: no

ethtool -i ile firmware ve driver özellikleri öğrenilebilir.

# ethtool -i eth0
driver: bnx2
version: 2.0.1-suse
firmware-version: 1.9.3
bus-info: 0000:04:00.0

Nic’in ağ istatistiklerini öğrenmek için ethtool -S kullanılabilir

# ethtool -S eth0
NIC statistics:
     rx_bytes: 74356477841
     rx_error_bytes: 0
     tx_bytes: 110725861146
     tx_error_bytes: 0
     rx_ucast_packets: 104169941
     rx_mcast_packets: 138831
     rx_bcast_packets: 59543904
     tx_ucast_packets: 118118510
     tx_mcast_packets: 10137453
     tx_bcast_packets: 2221841
     tx_mac_errors: 0
     tx_carrier_errors: 0
     rx_crc_errors: 0
     rx_align_errors: 0
     tx_single_collisions: 0
     tx_multi_collisions: 0
     tx_deferred: 0
     tx_excess_collisions: 0
     tx_late_collisions: 0
     tx_total_collisions: 0
     rx_fragments: 0
     rx_jabbers: 0
     rx_undersize_packets: 0
     rx_oversize_packets: 0
     rx_64_byte_packets: 61154057
     rx_65_to_127_byte_packets: 55038726
     rx_128_to_255_byte_packets: 426962
     rx_256_to_511_byte_packets: 3573763
     rx_512_to_1023_byte_packets: 893173
     rx_1024_to_1522_byte_packets: 42765995
     rx_1523_to_9022_byte_packets: 0
     tx_64_byte_packets: 3633165
     tx_65_to_127_byte_packets: 51169838
     tx_128_to_255_byte_packets: 3812067
     tx_256_to_511_byte_packets: 113766
     tx_512_to_1023_byte_packets: 104081
     tx_1024_to_1522_byte_packets: 71644887
     tx_1523_to_9022_byte_packets: 0
     rx_xon_frames: 0
     rx_xoff_frames: 0
     tx_xon_frames: 0
     tx_xoff_frames: 0
     rx_mac_ctrl_frames: 0
     rx_filtered_packets: 14596600
     rx_discards: 0
     rx_fw_discards: 0

Network düzgün çalışmıyorsa

• Speed ve Duplex değerlerinin “Unknown” olmasına
• Link detection değerinin No olmasına

bakılabilir.

Nic’in ledini yakmak için -p kullanılabilir

ethtool -p eth0

$ split --bytes=5M file.txt
 
$ ls -lh
-rw------- 1 ramesh programmers 15.2M Apr 2 13:13 file.txt
-rw------- 1 ramesh programmers 5.0M Apr 2 18:54 xaa
-rw------- 1 ramesh programmers 5.0M Apr 2 18:54 xab
-rw------- 1 ramesh programmers 5.0M Apr 2 18:54 xac
-rw------- 1 ramesh programmers 128K Apr 2 18:54 xad

Dosya isimlerinin daha anlamlı olması için prefix kullanılabilir

$ split --bytes=5M file.txt split_
 
$ ls -lh
-rw------- 1 ramesh programmers 5.0M Apr 2 18:54 split_aa
-rw------- 1 ramesh programmers 5.0M Apr 2 18:54 split_ab
-rw------- 1 ramesh programmers 5.0M Apr 2 18:54 split_ac
-rw------- 1 ramesh programmers 128K Apr 2 18:54 split_ad
-rw------- 1 ramesh programmers 15.2M Apr 2 13:13 file.txt

Dosyaları birleştirmek için

$ cat xa? > outfile.txt.zip
 
(or)
 
$ cat split_a? > outfile.txt.zip

zip hem Linux hem de windows kullanıcılarının açabileceği bir dosya formatı olarak
sıkıştırma için tercih edilebilir.

Bir adet dosyayı sıkıştırmak

zip output-file.zip input-file

Birden fazla dosyayı sıkıştırmak

zip output-file.zip input-file1 input-file2 input-file3 ...

Klasör sıkıştırmak

zip -r output-file.zip input-dir-name

Sıkıştırırken şifrelemek için -e kullanılabilir

zip -e output-file.zip intput-file

Sıkıştırılmış dosyaları açmak için

zip -e output-file.zip intput-file

lshal

lshw

bu sonuclarda “vendor” aranabilir.

lspci kullanılarak

lspci -vvnn

Boş satırları görmezden gelerek dosya karşılaştırmak

diff -w file1.txt file2.txt

    2c2
    < hscripts.com
    ---
    > HSCRIPTS.com
    4d3
    < Hioxindia.com

diff -y kullanarak satır satır karşılaştırma yapılabilir.
-b ile boş satırlar ihmal ediliyor

 diff -by file1.txt file2.txt
    HIOX TEST              HIOX TEST
    hscripts.com         | HSCRIPTS.com
    with friend ship       with   friend  ship
    Hioxindia.com        < 

diff -i ile case insensitive karşılaştırma yapılabilir.

diff -iy file1.txt file2.txt
    HIOX TEST              HIOX TEST
    hscripts.com           HSCRIPTS.com
    with friend ship     | with   friend  ship
    Hioxindia.com        <

Diff sonucunu okumak:

cat email                           
1 John erpl08@ed                
2 Joe  CZT@cern.ch              
3 Kim  ks@x.co                  
4 Keith keith@festival		
                                
                                

cat addresses
1 John erpl08@ed
2 Joe  CZT@cern.ch
3 Jean JRS@pollux.ucs.co
4 Jim  jim@frolix8
5 Kim  ks@x.co
6 Keith keith@festival

   diff email addresses
   2a3,4
   > Jean JRS@pollux.ucs.co
   > Jim  jim@frolix8

To make these files match you need to add (a) lines 3 and 4 (3,4) of the file addresses (>) after line 2 in the file email.

diff cookies.old cookies.new
5c5
< One cup vanilla extract
---
> One teaspoon vanilla extract
7d6
< Six ounces chopped liver
21a22
> Note: The previous version of this recipe had a few errors!

The output is actually a description of how to transform the old file into the new one. Here, diff is telling you three things:

· The fifth line of the file has undergone a change. The 5c5 message says to replace line 5 of the old file with line 5 of the new file. Both the old and new text are displayed, separated by a line of three dashes. (The less-than (<) notation means “remove this line,” and the greater-than (>) sign means “add this line.”)

· Line 7 of the old file does not appear in the new file. The 7d6 message says to delete line 7 from the old file, and the files will then be in sync, starting at line 6 of the new file. The text to be deleted is displayed on the next line.

· A line was added to the new file. The 21a22 message says to add a new line after line 21 of the old file. The text to be added is displayed on the final line of the output.

Veri dosyasinin içeriği:
”
406378:Sales:Itorre:Jan
031762:Marketing:Nasium:Jim
636496:Research:Ancholie:Mel
396082:Sales:Jucacion:Ed
”
olsun.

İlk 6 sütunun alınmasu

cut -c1-6 company.data 
406378 
031762 
636496 
396082 

4. ve 8. sütunun alınması

cut -c4,8 company.data 
3S 
7M 
4R 
0S 

seperator olarak “:” kullanıp 3. kolonu almak

cut -d: -f3 company.data 
Itorre 
Nasium 
Ancholie 
Jucacion 

-c [n | n,m | n-m] Specify a single column, multiple columns (separated by a comma), or range of columns (separated by a dash). -f [n | n,m | n-m] Specify a single field, multiple fields (separated by a comma), or range of fields (separated by a dash). -dc Specify the field delimiter. -s Suppress (don’t print) lines not containing the delimiter.

$ cat /etc/shells
# /etc/shells: valid login shells
/bin/csh
/bin/sh
/usr/bin/es
/usr/bin/ksh
/bin/ksh
/usr/bin/rc
/usr/bin/tcsh
/bin/tcsh
/usr/bin/esh
/bin/dash
/bin/bash
/bin/rbash
/usr/bin/screen
/bin/ksh93

Shell değiştirmek

$ echo $0
/bin/bash
 
$ exec /bin/sh
 
$ echo $0
/bin/sh

Kalıcı olarak shell değiştirmek

$ chsh -s /bin/sh
Password:

$ basename /usr/local/share/doc/foo/foo.txt
foo.txt
$ basename /usr/home/drobbins
drobbins

$ dirname /usr/local/share/doc/foo/foo.txt
/usr/local/share/doc/foo
$ dirname /usr/home/drobbins/
/usr/home

$ echo $(( 100 / 3 ))
33
$ myvar="56"
$ echo $(( $myvar + 12 ))
68
$ echo $(( $myvar - $myvar ))
0
$ myvar=$(( $myvar + 1 ))
$ echo $myvar
57

Toplama

$ echo '57+43' | bc
100

Çıkarma

$ echo '57-43' | bc
 
14

Çarpma

$ echo '57*43' | bc
 
2451

scale değişkeni sonucun virgülden sonrası için gösterilecek basamak adedini belirler.
Default değeri 0 dır.
-l ile kullanılırsa değeri 20 kabul edilir.

Bölme

$ echo 'scale=25;57/43' | bc
 
1.3255813953488372093023255

Karekök alma

$ echo 'scale=30;sqrt(2)' | bc
 
1.414213562373095048801688724209

Üs almak

$ echo '6^6' | bc
 
46656

Değişik tabanlarda işlem yapmak için obase ve ibase kullanabiliriz.
obase output tabanını belirler ve 2 ila 999 arasında değer alabilir.
ibase input tabanını belirler ve 2 ila 16 arasında değer alabilir.

255 sayısını 10 tabanından 16 tabanına çevirme:

$ echo 'obase=16;255' | bc
 
FF

2 tabanındaki sayıyı 10 tabanına çevirmek

$ echo 'ibase=2;obase=A;10' | bc
 
2

bc’yi bash içinde kullanmak için

$ FIVE=5 ; echo "$FIVE^2" | bc
 
25

bc’ye dosyadan işlem yaptırmak için “bc -q filename” kullanılabilir.
Dosya içeriği aşagıdaki gibi olabilir.

scale=2
 
/* C-style comments
   are allowed, as are spaces */
 
print "\nConvert Fahrenheit to Celsius\n\n"
print "Temperature in Fahrenheit: " ; fah = read()
print "\n"
print "Equivalent Temperature in Celsius is: "
(fah - 32.0) * 5.0 / 9.0
quit