Commands by haivu

Commands by haivu (54)

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Show the PATH, one directory per line (part 2)

Here is another way to show the path, one directory per line. The command `tr` translates the colon into the new line, taking input from the $PATH variable Show Sample Output
This is sample output - yours may be different.
```
/usr/local/bin
/usr/bin
/usr/local/sbin
/usr/sbin
```
3

tr : \\n <<<$PATH

haivu · 2018-08-28 20:01:04 430
Display two calendar months side by side

The Linux's `cal` command is nice, but there are times when I need to see two months side by side and this command will do it. Show Sample Output
This is sample output - yours may be different.
```
     August 2018           September 2018
Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa
          1  2  3  4                       1
 5  6  7  8  9 10 11     2  3  4  5  6  7  8
12 13 14 15 16 17 18     9 10 11 12 13 14 15
19 20 21 22 23 24 25    16 17 18 19 20 21 22
26 27 28 29 30 31       23 24 25 26 27 28 29
                        30
```
0

paste <(cal 8 2018) <(cal 9 2018)

haivu · 2018-08-28 19:54:05 1197
Shorthand to install package in Ubuntu

I put this line in my ~/.bashrc file (which I source via ~/.bash_profile). Now, when I need to install a package, I typed *install* instead of the longer version.
This is sample output - yours may be different.
-6

alias install='sudo apt-get install'

haivu · 2011-10-27 19:53:01 45
OSX: Hear pronunciation of a word

I often use this command to learn pronunciation of unfamiliar words.
This is sample output - yours may be different.
2

say WORD

haivu · 2010-03-26 15:23:32 8
Show the PATH, one directory per line

This is useful for examining the path. Show Sample Output
This is sample output - yours may be different.
```
/opt/local/bin
/opt/local/sbin
/usr/bin
/bin
/usr/sbin
/sbin
/usr/local/bin
/usr/X11/bin
```
6

printf ${PATH//:/\\n}

haivu · 2010-03-26 04:37:33 6
Start a HTTP server which serves Python docs

I use this command to start a local Python document server over HTTP port 8888.
This is sample output - yours may be different.
12

pydoc -p 8888 & gnome-open http://localhost:8888

haivu · 2010-02-28 07:01:43 17
MAC OS X: audible notification after a long command

I often run some command that takes a while to finish. By putting the say command afterward, I get an audio notification. Please note that this command (say) only works on Mac OS X and not Linux.
This is sample output - yours may be different.
-2

long_command; say I am all done

haivu · 2010-01-27 19:03:01 13
Show File System Hierarchy

Curious about differences between /bin, /usr/bin, and /usr/local/bin? What should be in the /sbin dir? Try this command to find out. Tested against Red Hat & OS X
This is sample output - yours may be different.
97

man hier

haivu · 2010-01-26 16:31:05 39

Command to Show a List of Special Characters for bash prompt (PS1)

I use this command (PS1) to show a list bash prompt's special characters. I tested it against A flavor of Red Hat Linux and Mac OS X Show Sample Output

This is sample output - yours may be different.

$ PS1
              \a     an ASCII bell character (07)
              \d     the  date in "Weekday Month Date" format (e.g., "Tue May
                     26")
              \D{format}
                     the format is passed to strftime(3) and  the  result  is
                     inserted into the prompt string; an empty format results
                     in a locale-specific time  representation.   The  braces
                     are required
              \e     an ASCII escape character (033)
              \h     the hostname up to the first '.'
              \H     the hostname
              \j     the number of jobs currently managed by the shell
              \l     the basename of the shell's terminal device name
              \n     newline
              \r     carriage return
              \s     the  name  of the shell, the basename of $0 (the portion
                     following the final slash)
              \t     the current time in 24-hour HH:MM:SS format
              \T     the current time in 12-hour HH:MM:SS format
              \@     the current time in 12-hour am/pm format
              \A     the current time in 24-hour HH:MM format
              \u     the username of the current user
              \v     the version of bash (e.g., 2.00)
              \V     the release  of  bash,  version  +  patch  level  (e.g.,
                     2.00.0)
              \w     the  current  working  directory, with $HOME abbreviated
                     with a tilde
              \W     the basename of  the  current  working  directory,  with
                     $HOME abbreviated with a tilde
              \!     the history number of this command
              \#     the command number of this command
              \$     if the effective UID is 0, a #, otherwise a $
              \nnn   the character corresponding to the octal number nnn
              \\     a backslash
              \[     begin a sequence of non-printing characters, which could
                     be used to embed a terminal control  sequence  into  the
                     prompt
              \]     end a sequence of non-printing characters

alias PS1="man bash | sed -n '/ASCII bell/,/end a sequence/p'"

haivu · 2010-01-15 23:39:28 4

List files that DO NOT match a pattern
This is sample output - yours may be different.
-1

ls | grep -vi pattern

haivu · 2009-11-24 20:39:53 6
Enable cd by variable names

Usage: mydir=/very/long/path/to/a/dir cd mydir I often need to cd where no man wants to go (i.e. long path). by enabling the shell option cdable_vars, I can tell cd to assume the destination is the name of a variable.
This is sample output - yours may be different.
4

shopt -s cdable_vars

haivu · 2009-10-26 22:10:56 5
Show bash's function definitions you defined in .bash_profile or .bashrc

If you omit the function name, the command will display all definitions Show Sample Output
This is sample output - yours may be different.
```
$ declare -f cd
cd () 
{ 
    builtin cd "${@:-$HOME}" && ls -F -G -H -hol
}
```
5

declare -f [ function_name ]

haivu · 2009-10-22 17:52:47 7
List bash functions defined in .bash_profile or .bashrc

If you issue the "set" command, you'll see a list of variables and functions. This command displays just those functions' names. Show Sample Output
This is sample output - yours may be different.
```
$ set | fgrep " ()"
.. () 
cd () 
h () 
ld () 
pg () 
today ()
```
1

set | fgrep " ()"

haivu · 2009-10-22 17:48:54 9
Extract a bash function

I often need to extract a function from a bash script and this command will do it. Show Sample Output
This is sample output - yours may be different.
```
$ sed -n '/^function h/,/^}/p' .bash_profile
function h() {
    if [ -z "$1" ]
    then
        history
    else
        history | grep "$@"
    fi
}
```
8

sed -n '/^function h/,/^}/p' script.sh

haivu · 2009-10-19 07:55:35 34
Execute a command before display the bash prompt

For example, if you are the type who type ls very often, then PROMPT_COMMAND=ls will ls after every command you issue.
This is sample output - yours may be different.
1

PROMPT_COMMAND=command

haivu · 2009-10-15 06:01:18 3
Display the history and optionally grep

Place this in your .bash_profile and you can use it two different ways. If you issue 'h' on its own, then it acts like the history command. If you issue: h cd Then it will display all the history with the word 'cd'
This is sample output - yours may be different.
7

h() { if [ -z "$1" ]; then history; else history | grep "$@"; fi; }

haivu · 2009-10-13 21:49:37 10
Find duplicate dir in path
This is sample output - yours may be different.
0

echo $PATH|tr : '\n'|sort|uniq -d

haivu · 2009-09-24 17:22:45 5
Show Directories in the PATH Which does NOT Exist

I often need to know of my directory in the PATH, which one DOES NOT exist. This command answers that question * This command uses only bash's built-in commands * The parentheses spawn a new sub shell to prevent the modification of the IFS (input field separator) variable in the current shell
This is sample output - yours may be different.
9

(IFS=:;for p in $PATH; do test -d $p || echo $p; done)

haivu · 2009-09-19 17:51:06 9
Delete all but the latest 5 files

I have a directory containing log files. This command delete all but the 5 latest logs. Here is how it works: * The ls -t command list all files with the latest ones at the top * The awk's expression means: for those lines greater than 5, delete.
This is sample output - yours may be different.
-2

ls -t | awk 'NR>5 {system("rm \"" $0 "\"")}'

haivu · 2009-09-16 04:58:08 4
Select and Edit a File in the Current Directory

This command displays a simple menu of file names in the current directory. After the user made a choice, the command invokes the default editor to edit that file. * Without the break statement, the select command will loop forever * Setting the PS3 prompt is optional * If the user types an invalid choice (such as the letter q), then the variable $f will become an empty string. * For more information, look up the bash's select command Show Sample Output
This is sample output - yours may be different.
```
$ select f in *;do vim $f; break; done
1) arguments		  5) getopt_homemade.sh	   9) remove_from_path.sh
2) data			  6) getopt_tryout	  10) scriptname.sh
3) for_example		  7) getopts_tryout	  11) var_substitution.sh
4) getopt_function.sh	  8) parameter_expansion
#? 4
```
8

PS3="Enter a number: "; select f in *;do $EDITOR $f; break; done

haivu · 2009-09-10 06:04:42 12
Identify long lines in a file

This command displays a list of lines that are longer than 72 characters. I use this command to identify those lines in my scripts and cut them short the way I like it.
This is sample output - yours may be different.
16

awk 'length>72' file

haivu · 2009-09-10 05:54:41 27
What is My WAN IP?

The curl command retrieve the HTML text containing the IP address. The grep command picks out the IP address from that HTML text. Show Sample Output
This is sample output - yours may be different.
```
$ curl -s checkip.dyndns.org | grep -Eo '[0-9.]+'
64.221.138.109
```
4

curl -s checkip.dyndns.org | grep -Eo '[0-9\.]+'

haivu · 2009-05-21 16:12:21 8
Which Version Is My Bash Shell?

This is one way to find out. Show Sample Output
This is sample output - yours may be different.
```
$ echo $BASH_VERSION
3.2.17(1)-release
```
-9

echo $BASH_VERSION

haivu · 2009-05-21 15:10:27 7
Vi - Matching Braces, Brackets, or Parentheses

This is a simple command for jumping to the matching brace, square bracket, or parentheses. For example, it can take you from the beginning of a function to the end with one key stroke. To delete everything between the pairs of {}, [], or (), issue the command: d% To replace text between pairs of braces, brackets, or parentheses, issue the command: c% You can also use this command to find out if an opening brace has been properly closed.
This is sample output - yours may be different.
7

%

haivu · 2009-05-21 15:02:39 10
Command Line to Get the Stock Quote via Yahoo

Retrieve the current stock price from Yahoo Finance. The output is simply the latest price (which could be delayed). If you want to look up stock for a different company, replace csco with your symbol. Show Sample Output
This is sample output - yours may be different.
```
19.58
```
11

curl -s 'http://download.finance.yahoo.com/d/quotes.csv?s=csco&f=l1'

haivu · 2009-05-04 08:13:59 28
1 2 3 >

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List your installed Firefox extensions

display a one-liner of current nagios exit statuses. great with netcat/irccat

list files recursively by size

View ~/.ssh/known_hosts key information

Will return the SSH server key information for each host you have in your ~/.ssh/known_hosts file, including key size, key fingerprint, key IP address or domain name, and key type.

List out classes in of all htmls in directory

Lists out all classes used in all *.html files in the currect directory. usefull for checking if you have left out any style definitions, or accidentally given a different name than you intended. ( I have an ugly habit of accidentally substituting camelCase instead of using under_scores: i would name soemthing counterBox instead of counter_box) WARNING: assumes you give classnames in between double quotes, and that you apply only one class per element.

Automator Bash script to create Clean zips in MacOS Finder without __MACOSX metadata

Finder compresses to ZIP but always includes extraneous metadata files (__MACOSX and .DS_Store) files and folders that may confuse other programs. One alternative is creating them and then editing the ZIP. This can work standalone or in an automator script accepting multiple selections (files or folders) and creating one zip per argument/selected file without that metada.

convert single digit to double digits

Uses 'rename' to pad zeros in front of first existing number in each filename. The "--" is not required, but it will prevent errors on filenames which start with "-". You can change the "2d" to any number you want, equaling the total numeric output: aka, 4d = ????, 8d = ????????, etc. I setup a handful of handy functions to this effect (because I couldn't figure out how to insert a var for the value) in the form of 'padnum?', such as: padnum5 () { /usr/bin/rename 's/\d+/sprintf("%05d",$&)/e' -- $@ } Which would change a file "foo-1.txt" to "foo-00001.txt"

fast access to any of your favorite directory.

example: -------------------------------------------------------------------------------------------- user@ubuntu:~/workspace/SVN/haystak-repos/trunk/internal/src$ addpi -------------------------------------------------------------------------------------------- Now that directory is in the list of fast access directories. You can switch to it anytime like this: -------------------------------------------------------------------------------------------- user@ubuntu:~$ pi internal` user@ubuntu:~/workspace/SVN/haystak-repos/trunk/internal/src$ -------------------------------------------------------------------------------------------- Please note the backquote ( the symbol that shares its key with ~ in the keyboard ) pi will switch you to that directory. To see the list of all fast access directories you have to say "cat ~/.pi"

List recorded formular fields of Firefox

When you fill a formular with Firefox, you see things you entered in previous formulars with same field names. This command list everything Firefox has registered. Using a "delete from", you can remove anoying Google queries, for example ;-)

Generate diff of first 500 lines of two files

Useful for massive files where doing a full diff would take too long. This just runs diff on the first 500 lines of each. The use of subshells to feed STDIN is quite a useful construct.

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