Bash/Zsh (shell): Sh scripting tricks

bash_zsh_tricks.sh

# run command on certain files in a directory
for file in ./myDir/*.abc
do
  cmd [options] $file > output.txt
done

# run command using integer ranges
for i in {1..5}
do
   echo "Welcome $i times"
done

# find files matching a pattern (escape *)
find . -name foo\*

# total line count for python source files
wc -l `find . -name '*.py'`

# change shell
chsh -s /bin/zsh

# get basename of file
basename myfile.ext .ext

# make a list variable
MYLIST=('hello' 'bye' 'awesome')
echo $MYLIST[1]

# to iterate over a list variable
for elem in "${MYLIST[@]}"
do
   # do whatever on $elem
done

# embed commands using back ticks
echo `basename myfile.ext .ext`

# replace \r's from windows to \n
cat filename.txt | tr '\r' '\n' > newfilename.txt