The `echo` command

Write arguments to the standard output. 66 examples from the lessons of the IVski Linux Playground — try them in the terminal next to them.

Examples

echo Hello, Linux!

echo 'hello' | tr 'a-z' 'A-Z'

Lowercase to uppercase

echo 'Hello World' | tr ' ' '_'

Replace spaces with _

echo 'hello' | tr -d 'l'

Delete all 'l' chars

echo $MYNAME

echo ${MYNAME}

Safer: braces avoid ambiguity

echo "Hello, ${MYNAME}!"

echo $?

Prints 0

echo $PATH

echo "Hello from my first script!"

echo "Today is: $(date)"

echo "You are: $(whoami)"

echo "Backup created: $BACKUP_DIR/backup-$DATE.tar.gz"

echo ${#NAME}

Length: 5

echo ${NAME,,}

Lowercase: ivski

echo ${NAME^^}

Uppercase: IVSKI

echo ${NAME:0:2}

Substring: IV

echo ${NAME/sk/SK}

Replace: IVSKi

echo ${FRUITS[0]}

apple

echo ${FRUITS[@]}

All elements

echo ${#FRUITS[@]}

Count: 3

echo "$fruit"

echo $((A + B))

echo $((A * B))

echo $((A / B))

3 (integer division)

echo $((A % B))

1 (remainder)

echo "Hello, IVski!"

echo "Not a guest"

echo "Name is empty"

echo "Name is set"

echo "Working age"

echo "Privileged user"

echo "Starts with IVsk"

echo "Starts with uppercase"

echo "Hello, $name!"

echo "Processing: $file"

echo "Count: $i"

echo "$i"

echo "Iteration: $COUNT"

echo "Line: $line"

echo "Running..."

echo "$COUNT"

echo "Hello, $1!"

echo "$content" > "$filename"

echo "Created: $filename"

echo $(date +%Y-%m-%d)

echo "Today: $TODAY"

echo "Found it!"

echo "[$(date +%H:%M:%S)] $1"

echo "Script name: $0"

echo "First arg:   $1"

echo "Second arg:  $2"

echo "All args:    $@"

echo "Arg count:   $#"

echo "Usage: $0 <source> <destination>"

echo "Copying $SRC to $DST"

echo "Argument: $1"

echo "file1 file2 file3" | xargs ls -la

echo '<h1>Hello from my server</h1>' | sudo tee /var/www/html/index.html

echo '<h1>About us</h1>' | sudo tee /var/www/html/about.html

echo secret | sudo tee /var/www/html/secret.html

echo '<h1>Welcome to the shop</h1>' | sudo tee /var/www/shop/index.html

echo '127.0.0.1 shop.local' | sudo tee -a /etc/hosts

echo "Requests: $(wc -l < ~/logs/access.log)"

$(…) puts a command's answer into the text

echo "…" >> ~/logs/health.log

>> adds a line, > would replace the file

echo "Hello, $1"

$1: the first word after the script's name