Shulou(Shulou.com)06/03 Report--

Shell outputs odd lines and even lines of the file respectively.

Awk

[root@114 ~] # awk 'NR%2==0' test.log output even number

2 warning: libgcc-4.4.7-4.el6.x86_64: Header V3 RSA/SHA1 Signature, key ID c105b9de: NOKEY

4 Installing filesystem-2.4.30-3.el6.x86_64

6 Installing ncurses-base-5.7-3.20090208.el6.x86_64

8 Installing glibc-common-2.12-1.132.el6.x86_64

10 Installing glibc-2.12-1.132.el6.x86_64

[root@114 ~] # awk 'NR%2==1' test.log output odd lines

1 Installing libgcc-4.4.7-4.el6.x86_64

3 Installing setup-2.8.14-20.el6_4.1.noarch

5 Installing basesystem-10.0-4.el6.noarch

7 Installing tzdata-2013g-1.el6.noarch

9 Installing nss-softokn-freebl-3.14.3-9.el6.x86_64

Sed

[root@114] # sed-n'nterterp 'test.log

2 warning: libgcc-4.4.7-4.el6.x86_64: Header V3 RSA/SHA1 Signature, key ID c105b9de: NOKEY

4 Installing filesystem-2.4.30-3.el6.x86_64

6 Installing ncurses-base-5.7-3.20090208.el6.x86_64

8 Installing glibc-common-2.12-1.132.el6.x86_64

10 Installing glibc-2.12-1.132.el6.x86_64

[root@114] # sed-n'ptern 'test.log

1 Installing libgcc-4.4.7-4.el6.x86_64

3 Installing setup-2.8.14-20.el6_4.1.noarch

5 Installing basesystem-10.0-4.el6.noarch

7 Installing tzdata-2013g-1.el6.noarch

9 Installing nss-softokn-freebl-3.14.3-9.el6.x86_64

[root@114 ~] # sed-n '1mm 2p' test.log

1 Installing libgcc-4.4.7-4.el6.x86_64

3 Installing setup-2.8.14-20.el6_4.1.noarch

5 Installing basesystem-10.0-4.el6.noarch

7 Installing tzdata-2013g-1.el6.noarch

9 Installing nss-softokn-freebl-3.14.3-9.el6.x86_64

[root@114 ~] # sed-n '2cm 2p' test.log

2 warning: libgcc-4.4.7-4.el6.x86_64: Header V3 RSA/SHA1 Signature, key ID c105b9de: NOKEY

4 Installing filesystem-2.4.30-3.el6.x86_64

6 Installing ncurses-base-5.7-3.20090208.el6.x86_64

8 Installing glibc-common-2.12-1.132.el6.x86_64

10 Installing glibc-2.12-1.132.el6.x86_64

Sed'1x 2p 'where 1 represents firest line,2, represents interval step, output line = 1x 2n, odd line

Sed '2cm 2p' output line = 2x 2n, even lines

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