Commands

• 1. tr

• 2. cut

• 3. tee

• 4. grep

• 5. find

  • 5.1. find + -exec

  • 5.2. find + xargs

1. tr

tr – translate characters

e.g.

tr ':' '\n' <<< "$PATH"

• -d: Delete characters in string from the input.

2. cut

The default field delimiter for cut is (tab).

cut – cut out selected portions of each line of a file

e.g.

cut -d ":" -f 1,4 /etc/passwd

• -d delim: Use delim as the field delimiter character instead of the tab character.

• -f list: The list specifies fields, separated in the input by the field delimiter character (see the -d option). Output fields are separated by a single occurrence of the field delimiter character.

3. tee

tee – duplicate standard input

The tee command is used to read from standard input and write to both standard output and one or more files simultaneously.

e.g.

Send the echoed message to both stdout and to the output.txt file:

$ echo "Hello" | tee output.txt
Hello

4. grep

• -v, --invert-match: Selected lines are those not matching any of the specified patterns.

• -r, -R, --recursive: Recursively search subdirectories listed. (i.e., force grep to behave as rgrep).

• -i, --ignore-case: Perform case insensitive matching. By default, grep is case sensitive.

• -E, --extended-regexp: Interpret pattern as an extended regular expression (i.e., force grep to behave as egrep).

Use pattern:

$ grep -E "pyenv" .zshrc
# pyenv
eval "$(pyenv init -)"

$ grep -E "pyenv$" .zshrc
# pyenv

Match empty lines:

grep -E "^$" .zshrc

5. find

5.1. find + -exec

5.2. find + xargs

E.g.

find . -name "*.sh" -print0 | xargs -0 grep "<content>"