• Directory
  • dirs
• Search and Replace
  • find
  • grep
• time
  • time

This blog only lists SOME arguments of a command.

Directory

dirs

 dirs [-clpv] [+N | -N] 

Display the list of currently remembered directories. Directories are added to the list with the pushd command; the popd command removes directories from the list. Click here for more details.

 popd [-n] [+N |-N] 

Remove the top entry from the directory stack, and cd to the new top directory. When no arguments are given, popd removes the top directory from the stack and performs a cd to the new top directory. The elements are numbered from 0 starting at the first directory listed with dirs; that is, popd is equivalent to popd +0.

 pushd [-n] [+N | -N | dir] 

Save the current directory on the top of the directory stack and then cd to dir. With no arguments, pushd exchanges the top two directories

 pushd [-n] [+N | -N | dir] 

Save the current directory on the top of the directory stack and then cd to dir. With no arguments, pushd exchanges the top two directories.

Search and Replace

find

Click here for more examples.

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# Print out a list of all the files with name "foo"
find / -name "foo" -print

# Print out a list of all the files with name "foo", 
# but the search is case insensitive
find / -iname "foo" -print

# Print out a list of all the files whose names do not end in .c.
find / \! -name "*.c" -print

# Print out a list of all the files owned by user ``wnj'' that are 
# newer than the file ttt.
find / -newer ttt -user wnj -print

# Print out a list of all the files which are not both newer than 
# ttt and owned by ``wnj''.
find / \! \( -newer ttt -user wnj \) -print

# Print out a list of all the files that are either owned by ``wnj'' 
# or that are newer than ttt.
find / \( -newer ttt -or -user wnj \) -print

# Print out a list of all the files whose inode change time is more 
# recent than the current time minus one minute.
find / -newerct '1 minute ago' -print

# Find files and directories that are at least seven levels deep in 
# the working directory /usr/src.
find /usr/src -name CVS -prune -o -depth +6 -print

-exec COMMAND \;

Carries out COMMAND on each file that find matches. The command sequence terminates with “;” (the “;” is escaped to make certain the shell passes it to find literally, without interpreting it as a special character).

If COMMAND contains {}, then find substitutes the full path name of the selected file for “{}”.

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# Use the echo(1) command to print out a list of all the files.
# Do not confuse the option -exec with the exec shell builtin.
find / -type f -exec echo {} \;

# Delete all broken symbolic links in /usr/ports/packages.
find -L /usr/ports/packages -type l -exec rm -- {} +

grep

The grep utility searches any given input files, selecting lines that match one or more patterns. By default, a pattern matches an input line if the regular expression (RE) in the pattern matches the input line without its trailing newline. An empty expression matches every line. Each input line that matches at least one of the patterns is written to the standard output.

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# Select lines that contain "foo" in file "some_file".
grep foo some_file

# Select lines that contain "foo" in file "some_file" insensitively.
grep -i foo some_file

# Select lines that contain "foo" in file "some_file", 
# and precede each line by its relative line number.
grep -n foo some_file

# Only the names of files containing selected lines are listed.
# This argument is usually combined with -r or the find command.
grep -l foo some_dir

# Select lines that do not contain "foo" in file "some_file".
grep -v foo some_file

grep can also be combined with find:

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# Search for "foo" in all the .cpp files
find / "*.cpp" -exec grep foo {} \;

time

time

time [-lp] utility

This command can be used to measure the clock time, user time and system time of process “utility”. The output format depends on your shell being used.

$time grep -rl "test" .  > test.txt

Output:

real	0m0.011s
user	0m0.004s
sys	0m0.005s

• real time: the amount of time the process takes to run, and its value depends on the number of other processes running on the system.
• user time: the cpu time attributed to user instructions.
• sys time: the cpu time attributed to the kernel when it executes on behalf of the process.