Mark Pearl

08 June 2014

Bash Notes

Outline

Manipulating Files

Copying Files

cp temp.sh file5.sh

copy temp.sh as file5.sh

cp temp* ..

copy files starting with temp to the parent folder.

cp -R files/ backup/

copy all files and subdirectories to the backup directory

Copying files means you are creating a file, which means you take ownership.

cp -a file1.txt file2.txt

copy files in archive mode, which maintains original ownership

Deleting Files & Directories

rmdir

deletes empty directories

rm -rf directoryName

recursively deletes directory and all of its content

Moving or Renaming Files

mv temp.sp new.sh

Compressing a File

tar stands for tape archive

tar -c -v -f file.sp

creates a tar archive

tar -c -z -v -f directoryName

-z means to zip it up

Decompressing a File

tar -xzf file.tar

-x Extract to disk
-z Zip/compress -f Filename

Directory Structure

sudo apt-get install tree

Show all directories except one

tree -d -I "dirToIgnore"

Navigate to previous directory

cd -

Navigate to user directory

cd ~

Navigate to home directory

cd

Searching

List

displays a listing with full format

ls -l

displays the file size in megabytes ####

ls -lah

displays the file or directory type in the listing

ls -F

diplays listing with color

ls --color=auto

displays file in hum readable list style with size

ls -lah

Find

find . -newer file1

finds all files in the current and children directory that are newer than file1

find . -newer file1 -delete

finds and deletes all file in the current and children directory that are newer than file1

find . -name "*FileNameToMatch*"

find . -iname "*stuff*"

**Find -flags **

finds all files in the current and children directory that match the FileNameToMatch

Finding Files using Regex

Find any files with ‘stuff’ in them

find . -iregex ".*stuff.*"

.* is equivalent to wildcard

By default regex checks the entire path. There is an implicit ^..$ implied which means “stuff” is actually “^stuff$”

Open First found file in Vim

vim $(find -name somefile.txt)

find -name somefile.txt -exec vim {} \;

Directory Management

Remove directory and all sub directories

rm -r dir

Remove directory and all sub directories (force)

rm -fr dir

Make directory

mkdir dir

Imaging Tasks

rsync -av directoryName locationOfBackup

synchronizes copies

rsync -av --delete directoryName locationOfBackup

syncrhonizes deletions

Search tool

Search is case sensitive unless otherwise specified

grep Server /etc/ntp.conf

Search without case

grep -i

Removes commented lines ^# and empty lines ^$
The -ve means an additional expression.

grep -ve '^#' -ve '^$' /etc/ntp.conf

The stream editor, edits the inline stream -i stands for the inplace update

sed -i '^#/d;^$/d' /etc/ntp.conf

-E stands for a full regex expression

grep -E 'regex'

Manipulating Output

Translate / Delete

tr [OPTION] SET1 [SET2] 

$ tr abcde ABCDE somestuf
somEstuf

$ echo 'hello' | tr abcde ABCDE  
hEllo

$ echo 'hello' | tr -d 'e'
hllo

Unique Values

uniq

Word Count

wc

Process Management

bg

Moves the current process into the brackground

ps

sleep 200 &

The & automatically starts a job in the background process

jobs

Shows a list of the current jobs

fg 1

Brings job number one into the foreground

pgrep

Searches for a current process

ps -l

Shows a long listing

ps -e

Shows all processes

pkill sleep

Kills the sleep process

kill -9 procnum

Really kills the process

top -n 1

The swiss army knife of processes

Analyze Text Files

Please note we use test.sh as a placeholder for the file you are performing the action on.

Piping Output to a File

>

e.g. ls > test.sh

Pipe to vim to check syntax

11 | gvim --

Show contents of file

cat test.sh

Making Files Exectuable

chmod +x test.sh

Making Files Writeable

chmod 777 test.sh

Removing unrecognized dos characters

dos2unix test.sh

Cut

Cut can be used to display only certain fields within a file.

cut -f1,3 -d";" !$

Displays field 1 and field 3 of a delimitered file using ; as the delimiter where !$ was the last argument used (in this case cat test.sh).

Customization

Setup Alias’s

Edit the file in the following location: ~/.bashrc

alias doSomething='commands'

Enable vi mode in bash

To make this permanent, add to to ~./bash_profile file

set -o vi

Managing Processes

Go to the /proc directory, if you perform a ls it will show you all the processes running currently. Running cat on the file mounts will show you all the drives currently mounted.

Starting / Stopping Jobs

& - start a job in the background

google-chrome &

Foreground / Background

fg,bg - put a job in the foreground / background

fg %2	# send job with id 2 to the foreground
fg %vi	# send job with process name 'vi' to foreground

Kill

kill %1            # kill by job id 1  
kill 12345         # kill by process id  
kill -KILL 12345   # hard kill  
xkill 		   # kill by clicking its window
pkill		   # kill process by matching filenames

List Processes

ps -ef		   # list all processes in long format
top		   # list and manage top processes

Manipulating Output

Head and Tails

Head shows the first ten lines of a file.
Tail shows the last ten lines of a file.

head -n 3 test.sh

The above shows the first 3 lines of test.sh

tail -f

The above follows the end of a file. Ctrl+C stops the following.

More and Less

More allows us to page forward through a file.
Less allows us to page forward, backward and to a specific location in a file.

Sort

Sort can be used to order the columns as desired. Sort without defining a column sorts on the first column.

sort -r test.sh

Sort numerically

sort -n

Reverse sort

sort -r

Sort the fourth column using , as the delimiter on the last command run.

sort -k4 -t"," !$

Sort and shows only unique results.

sort -u

Environment Variables

Show Currently Defined Variables

env

Favorite Environment Variables

PATH 	# where bash looks for executables  
PS1	# the prompt
EDITOR  # your preferred editor

Working with Environment Variables

Printing a variable to the screen

echo $PATH

Temporarily changing a variable value

PATH="$PATH:~/bin"

Other

Piping & Redirection

Output Redirection

Save Output to File, Overwrite if file already exists

ls > file.txt

Save Output to File, Append to file already exists

ls >> file.txt

Input Redirection

Get input from file and direct it to command

<

grep x < file

Pipe

Redirect output from one program to input of another program

ls | grep hello

Command Substitution

cat $($ls -rt | tail -n1)

List Disks

fdisk -l

Clear the Screen

Ctrl+L - clears the console

Run with Root Privelages

sudo -i

Run the Last Command Again

!$

Git Aware Prompt

Read more here

Show History of Commands

history

Add custom autocomplete commands to bash

  1. Download the attached commands.txt file to your git bash home folder

a. I need to figure out a way to keep this updated easier, currently I run the console with no parameters and manually copy the command names into the file

  1. In your git bash home, open (or create) your .bash_profile file

  2. Add the following lines, adjusting kbrepo to where your console is built

kbrepo=/c/src/Keyblade/Keyblade alias kbc=’$kbrepo/KeyBlade.UI.Console/bin/Debug/Keyblade.UI.Console.exe c’ export COMMAND_FILE=~/commands.txt _kbcommands() { local cur=${COMP_WORDS[COMP_CWORD]} COMPREPLY=( $( compgen -W “$(cat ${COMMAND_FILE})” – $cur ) ) } complete -F _kbcommands kbc

  1. Now you can use ‘kbc [TAB]’ and it will show you a list of commands.

  2. OR

  3. kbc Ack[TAB] è kbc AcknowledgeConsoleFailures

Viewing PDF’s

Use okular

Display disk space

df

References

Bash stuff from Coderwall
Bash History
Introduction to Bash on PluralSight
Bash Cheat Sheet

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