diff

• see differences between two files (works for text)

• options for ignoring white space

grep

• print lines from the input file (or stream) that match a given expression

• find all occurences of the string "Joanna" in all files in the current directroy (do it recursively)

  grep  -R "Joanna" *

• find all occurences of the string "open source" in the files stored in ~/Data/NYU_Teaching/csci480_ossd/, don't go into subdirectories

  grep  "open source" ~/Data/NYU_Teaching/csci480_ossd/*

sort

• sort the lines coming from the input file or from standard input

• default order: alphanumeric

• -n option uses numerical order

• -r option reverses the order

cut

• print specific parts (columns, characters) of the input file/stream

• options allow to select columns (individual 1-base numbers) or ranges of columns (comma-separated values: 1,3,8 or range: 3-7)

• -f option specifies column numbers (default column separator is a tab)

• -c option specifies character positions

• -d option changes the default separator

paste

• combines input from multiple files into a single "line by line" output

find

find -name

find files with names matching a string

• find all files in my home directory matching string "ossd"

  find ~ -name "*ossd*"

  • ~ shortcut for the home directory of the current user
  • *ossd* pattern to match

• find all files in the current working directory matching string "bugs"

  find . -name 'bugs'

• find all files in the specified directory matching the string "cs102" at the start of the file/directory name

  find . -name 'cs102*'

find -size

find files based on their size

• find all files in the current working directory that are larger than 512M

  find . -size +512M

find -mtime (-atime)

find files that have been modified (mtime) or accessed (atime) within specified number of days (for minutes use mmin and amin options)

• find all files in the current working directory that have been modified within the last two days

  find . -mtime -2

find -perm

find files with specific permissions

• find all files in user's home directory with wide open permissions

  find ~ -perm 777

• find all image files larger than 3MB

  find ~ -size +3M -a \( -name "*.jpg" -o -name "*.png" -o -name "*.gif" \)
  `