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Every Nth line position # (SED)

sed extract every nth line. Generic is: sed -n 'STARTPOSITION,${p;n;*LINE}' foo where n;*LINE = how many lines. thus p;n;n; is "for every 3 lines" and p;n;n;n;n; is "for every 5 lines" Show Sample Output
This is sample output - yours may be different.
```
$ sed -n '1,${p;n;n;}' blah1
1
4
7

$ sed -n '2,${p;n;n;}' blah1
2
5
8

$ sed -n '3,${p;n;n;}' blah1
3
6
9
```
1

sed -n '1,${p;n;n;}' foo > foo_every3_position1; sed -n '2,${p;n;n;}' foo > foo_every3_position2; sed -n '3,${p;n;n;}' foo > foo_every3_position3

oshazard · 2010-01-08 04:19:59 4
List all authors of a particular git project

This should work even if the output format changes.
This is sample output - yours may be different.
18

git log --format='%aN' | sort -u

jedahan · 2010-01-07 18:55:21 63
List all authors of a particular git project

List everyone who committed to a particular project, listed alphabetically. To list by commits, add -n to the shortlog. Show Sample Output
This is sample output - yours may be different.
```
Foo Bar
Bob Barker
BBlum
```
4

git shortlog -s | cut -c8-

jedahan · 2010-01-07 18:04:01 4
Rename .JPG to .jpg recursively

Recursively rename .JPG to .jpg using standard find and mv. It's generally better to use a standard tool if doing so is not much more difficult.
This is sample output - yours may be different.
7

find /path/to/images -name '*.JPG' -exec bash -c 'mv "$1" "${1/%.JPG/.jpg}"' -- {} \;

sorpigal · 2010-01-07 15:41:17 8
Print a row of 50 hyphens

In bash, by pressing ALT+n and then a character x, x will be printed n times I know is not the same as the original command, but is correlated. Show Sample Output
This is sample output - yours may be different.
```
$ --------------------------------------------------
```
-3

<alt+50>-

kobayashison · 2010-01-07 15:32:47 5
Prints line numbers

If you don't have nl on your system, this achieves a similar effect, the default behavior in nl is to not number blank lines, but this does.
This is sample output - yours may be different.
2

grep -n "^" <filename>

JohnGH · 2010-01-07 14:54:29 3
Print a row of 50 hyphens
This is sample output - yours may be different.
0

python -c 'print "-" * 50'

4Aiur · 2010-01-07 13:11:44 4
Add a line to crontab using sed

I needed to add a line to my crontab from within a script and didn't want to have to write my own temporary file. You may find you need to reload the crond after this to make the change take effect. e.g.: if [ -x /sbin/service ] then /sbin/service crond reload else CRON_PID=`ps -furoot | awk '/[^a-z]cron(d)?$/{print $2}'` if [ -n "$CRON_PID" ] then kill -HUP $CRON_PID fi fi The reason I had CRON_HOUR and CRON_MINS instead of numbers is that I wanted to generate a random time between midnight & 6AM to run the job, which I did with: CRON_HOUR=`/usr/bin/perl -e 'printf "%02d\n", int(rand(6))'` CRON_MINS=`/usr/bin/perl -e 'printf "%02d\n", int(rand(60));'`
This is sample output - yours may be different.
-1

crontab -l | sed -e '$G;$s-$-'"$CRON_MINS $CRON_HOUR"' * * * /usr/bin/command >/dev/null 2>&1-' | crontab -

JohnGH · 2010-01-07 11:00:05 6
Print a row of 50 hyphens

Better -and faster- using bash printf. Show Sample Output
This is sample output - yours may be different.
```
$ time printf "%50s\n"|tr \  -
--------------------------------------------------

real	0m0.008s
user	0m0.000s
sys	0m0.008s
```
-2

printf "%50s\n"|tr ' ' -

rodolfoap · 2010-01-07 08:49:46 6
Watch the size of a directory using figlet

You can substitute /home/$USER with any path you like.
This is sample output - yours may be different.
3

watch -n1 "du -hs /home/$USER | cut -f1 -d'/' | figlet -k"

cviorel · 2010-01-07 07:30:59 6
Resize a Terminal Window

Replace 70 with the desired height. Replace 180 with the desired width. I put it in my bashrc, because by default my terminal is too small.
This is sample output - yours may be different.
4

printf "\e[8;70;180;t"

jearsh · 2010-01-07 05:58:16 38
Pretty man pages under X
This is sample output - yours may be different.
8

function manpdf() {man -t $1 | ps2pdf - - | epdfview -}

Aparicio · 2010-01-07 02:05:03 4
Pretty man pages under X

You're a developer - but it doesn't mean you have to slum it! Why not spice up your man page lookups by using a decent PDF viewer. I use 'xpdf' - maybe you prefer acroread, whatever, it's just as fast as plain dull ASCII on today's machines and you can still search for stuff - that's the main reason I use PDF and not PS.
This is sample output - yours may be different.
1

vman(){ T=/tmp/$$.pdf;man -t $1 |ps2pdf - >$T; xpdf $T; rm -f $T; }

bhepple · 2010-01-07 01:15:38 5
Fix borked character coding in a tty.

Often you find some tty programs are messed up and confused about character encoding - 'man' is a common problem and sometimes displays weird characters for apostrophes, hyphens etc etc. Another class of programs that suffer from this are those that try to use the line drawing characters - eg RedHat's tty system admin functions such as system-config-firewall-tui system-config-network-tui etc. Adding 'LC_ALL=C' fixes most of these problems (as long as you want English! Perhaps speakers of other languages can add a comment here). For bonus points, I've added the '-c' option to the man command so that it ignores it's cache and re-computes the man page using the C locale.
This is sample output - yours may be different.
1

LC_ALL=C man -c man

bhepple · 2010-01-07 00:59:09 4
Print a row of 50 hyphens
This is sample output - yours may be different.
1

ruby -e 'puts "-" * 50'

unixmonkey7743 · 2010-01-06 21:14:25 33
live ssh network throughput test

connects to host via ssh and displays the live transfer speed, directing all transferred data to /dev/null needs pv installed Debian: 'apt-get install pv' Fedora: 'yum install pv' (may need the 'extras' repository enabled) Show Sample Output
This is sample output - yours may be different.
```
136MB 0:00:22 [5.71MB/s] [    <=>         ]
```
11

pv /dev/zero|ssh $host 'cat > /dev/null'

opertinicy · 2010-01-06 20:40:51 7
Show git branches by date - useful for showing active branches
This is sample output - yours may be different.
6

for k in `git branch|sed s/^..//`;do echo -e `git log -1 --pretty=format:"%Cgreen%ci %Cblue%cr%Creset" "$k"`\\t"$k";done|sort

unixmonkey7740 · 2010-01-06 18:35:29 6
Colored diff ( via vim ) on 2 remotes files on your local computer.

You can use vim scp://root@example.com//file too in a simple case.
This is sample output - yours may be different.
17

vimdiff scp://root@server-foo.com//etc/snmp/snmpd.conf scp://root@server-bar.com//etc/snmp/snmpd.conf

sputnick · 2010-01-06 18:12:45 14
use sed to simulate rpad and lpad

the sql command lpad and rpad using sed for lpad, invert the &_ with _&: ls / | sed -e :a -e 's/^.\{1,15\}$/_$/;ta' Show Sample Output
This is sample output - yours may be different.
```
bin_____________
boot____________
cdrom___________
dev_____________
etc_____________
home____________
```
0

ls / | sed -e :a -e 's/^.\{1,15\}$/&_/;ta'

glaudiston · 2010-01-06 17:22:01 3
Print a row of 50 hyphens

the sed way to print a linhe with 50 hyphens
This is sample output - yours may be different.
0

echo - | sed -e :a -e 's/^.\{1,50\}$/&-/;ta'

glaudiston · 2010-01-06 17:18:15 4
Print a row of 50 hyphens

Perl is installed by default on most modern OS when jot is not. Show Sample Output
This is sample output - yours may be different.
```
--------------------------------------------------
```
4

perl -le'print"-"x50'

sputnick · 2010-01-06 17:06:07 4
Do a search-and-replace in a file after making a backup

sed already has an option for editing files in place and making backup copies of the old file. -i will edit a file in place and if you give it an argument, it will make a backup file using that string as an extension.
This is sample output - yours may be different.
3

sed -i.bak 's/old/new/g' file

deltaray · 2010-01-06 17:04:05 3
Print a row of 50 hyphens
This is sample output - yours may be different.
0

jot -s '' -b '-' 50

putnamhill · 2010-01-06 16:59:24 3
Print a row of 50 hyphens

Change the number 50 to whatever number of characters you want. Change the character inside the double quotes to whatever you want printed.
This is sample output - yours may be different.
0

awk 'BEGIN{while (a++<50) s=s "-"; print s}'

SuperFly · 2010-01-06 16:16:35 36
Prints line numbers

Works in RHEL5 and derivatives.
This is sample output - yours may be different.
-1

nl <filename>

SuperFly · 2010-01-06 16:14:43 3
‹ First < 411 412 413 414 415 > Last ›

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Remove grep itself from ps

When you 'ps|grep' for a given process, it turns out that grep itself appears as a valid line since it contains the RE/name you are looking for. To avoid grep from showing itself, simply insert some wildcard into process' name.

bash/ksh function: given a file, cd to the directory it lives

fcd : file change directory A bash function that takes a fully qualified file path and cd's into the directory where it lives. Useful on the commadline when you have a file name in a variable and you'd like to cd to the directory to RCS check it in or look at other files associated with it. Will run on any ksh, bash, likely sh, maybe zsh.

convert unixtime to human-readable

Advanced python tracing

Trace python statement execution and syscalls invoked during that simultaneously

Put uppercase letters in curly brackets in a BibTeX database

It is often recommended to enclose capital letters in a BibTeX file in braces, so the letters will not be transformed to lower case, when imported from LaTeX. This is an attempt to apply this rule to a BibTeX database file. DO NOT USE sed '...' input.bib > input.bib as it will empty the file! How it works: $ /^\s*[^@%]/ Apply the search-and-replace rule to lines that start (^) with zero or more white spaces (\s*), followed by any character ([...]) that is *NOT* a "@" or a "%" (^@%). $ s===g Search (s) for some stuff and replace by other stuff. Do that globally (g) for all matches in each processed line. $ $[A-Z][A-Z]*$$[^}A-Z]\|},$$ Matches at least one uppercase letter ([A-Z][A-Z]*) followed by a character that is EITHER not "}" and not a capital letter ([^}A-Z]) OR (|) it actually IS a "}", which is followed by "," at the end of the line ($). Putting regular expressions in escaped parentheses ($ and $, respectively) allows to dereference the matched string later. $ {\1}\2 Replace the matched string by "{", followed by part 1 of the matched string (\1), followed by "}", followed by the second part of the matched string (\2). I tried this with GNU sed, only, version 4.2.1.

Put split files back together, without a for loop

After splitting a file, put them all back together a lot faster then doing $cat file1 file2 file3 file4 file5 > mainfile or $for i in {0..5}; do cat file$i > mainfile; done When splitting, be sure to do split -d for getting numbers instead of letters

Search commandlinefu from the command line

There's probably a more efficient way to do this rather than the relatively long perl program, but perl is my hammer, so text processing looks like a nail. This is of course a lot to type all at once. You can make it better by putting this somewhere: $ clf () { (curl -d "q=$@" http://www.commandlinefu.com/search/autocomplete 2>/dev/null) | egrep 'autocomplete|votes|destination' | perl -pi -e 's/$/\n\n/g;s/^ +|\([0-9]+ votes,//g;s/^\//http:\/\/commandlinefu.com\//g'; } Then, to look up any command, you can do this: $ clf diff This is similar to http://www.colivre.coop.br/Aurium/CLFUSearch except that it's just one line, so more in the spirit of CLF, in my opinion.

Find and copy scattered mp3 files into one directory

I used this command to recursively gather all mp3 files that were previously imported into their own directories (sorted by band name) in Songbird.

Use AbiWord to generate a clean HTML document from a Microsoft Word document.

Credit goes to @Porges from http://stackoverflow.com/questions/67964/what-is-the-best-free-way-to-clean-up-word-html.

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