BASIC SHELL

COMMANDS

!! - repeat last command

VARIABLES

foo=bar
echo $foo

ARGUMENTS

$0 - name of script $# - number of arguments $@ - all argumets in list (separated by space) $* - all arguments as a single string $1..$9 - arguments $? - get the error code from prewious if OK then this is 0 $_ - get the last argument from last cmd

CONDITIONAL COMMAND EXECUTION

false || echo "Will be printed"
true && echo "This wet ok"
true; false; echo "will execute secuentally"

COMMAND OUTPUT INTO VARIABLE

foo=$(pwd)
echo $foo

echo "We are in $(pwd)"

SAVE OUTPUT TO TMP_FILE

cat <(ls) <(ls ..)

FLUSH COMMAND OUTPUT & ERROR

grep foobar "$file" > /dev/null 2> /dev/null

IF STATEMENT

glej:

man test

if [[ $? -ne 0 ]]; then
  echo "Error found..."
  echo "... Fixing error."
fi

GLOBBING (EXPAND TO DIFFERENT FILES)

ls filename?.txt
ls ?.txt

EXPANDING THE COMMANDS ARGUMENTS

touch test_file{1,2,3}.md
touch test_file_{a..z}.md

COMPARE FILES

diff file1 file2
#compare the dirrectory content
diff <(ls dir1) <(ls dir2)

DEBUGGING

shellcheck bash_script.sh
#give you more info where and how the program is broken

NAVODILE

za skoraj vse ukaze najdemo navodila tako da:

# navodila kako uporabljati ukaz
man ukaz
# primeri kako uporabljati ukaz
tldr ukaz

HISTORY OF COMMANDS

#use arrows
history
history 1 | grep convert
# CTRL+R .. search trough history
fzf
# history substring search

LISTING AND FILE HANDELING

ls -R
tree
broot
nnn
ranger