CLI Utilities

Probe what program or alias the following will execute.

Show the location of binary, source code (if available), and manpage.

Show the manpage entry.

Fuzzy-find through the manpages.

It has been Unix tool for a while.

• slocalte (secure locate), mlocate (merging locate), plocate (posting locate) are the implementations in order.
  • locate symlinks to the specific implementation.
• updatedb command needs to run to build the databse at /var/lib/plocate/plocate.db.
• plocate
  • It uses trigrams to index the database the index is inverted (from trigrams to files)

find [STARTING_POINTS...] EXPRESSION

• STARTING POINT is any directory or file
  • Multiple of them can be given and each one of them is traversed left to right.
  • Current directory is assumed when not given.
• EXPRESSION: any expression evaluates to either true or false.
  • Global: Always true
    • -maxdepth N: 0 means the starting point itself, and 1 means the child of it, and so on.
    • -mindepth N: does not evaluate the expression when depth is less than N
  • Test: true if matched
    • -name PATTERN: match the file name using the shell file name pattern (*, ?)
    • -iname PATTERN: case insensitive match
    • -path PATTERN: match the entire file path to the pattern.
    • -regex PATTERN: use regular expression to match the file name.
    • -type {b|c|f|s|...} match the file type
    • -size N[k|M|G] size of N kilo/mega/gigabytes.
    • -amin N, accessed N miniutes ago, -atime N accessed N days ago
      • +N or -N can be used to indicate "more than" and "less than".
      • -cmin N, -ctime N, -mmin N, -mtime N for changes and modified reprectively.
  • Action: true on seccess.
    • -delete
    • -exec COMMAND \;: run the command for the matched file. '{}' is replaced by the file name. Note that \ and ' are there to prevent the shell parsing it.
    • -print: print the full file name
    • -prune: stop descending further into this directory.
    • -quit: exit.
  • Operator
    • \( EXPR \): force precedence
    • \! EXPR, -not EXPR (not POSIX): true if EXPR is false.
    • EXPR1 EXPR2, EXPR1 -a EXPR2, EXPR1 -and EXPR2 (not POSIX)
    • EXPR1 -o EXPR2, EXPR1 -or EXPR2 (not POSIX): it has lower precedence than AND.
    • EXPR1 , EXPR2: EXPR1 is evaluated and discared. The value of EXPR2 is the value of the list.
• -print is implicit after the whole expression, unless -delete, -exec, -print, … is used.

Take a path pattern and return the information of directories along the path.

Set the creation file mode for the current environment.

• mknod [OPTION] NAME TYPE [MAJOR] [MINOR]
• -m --mode=MODE permission mode
• TYPE
  • b buffered block file
  • c u buffered/unbuffered character file
  • p FIFO
• MAJOR MINOR
  • It must be specified for b c u
  • 0x 0X 0 == hexadecimal, octal, decimal

• Divide a file into smaller ones.
• -b: size, -n: division, -l line, --filter 'gzip > $FILE.gz': post-action hook.

The splitted files can be combined with cat on Linux, copy /b FILE1 + FILE2 OUTFILE on Windows.

7z -v SIZE also does the simple split on the compressed file.

• Creates hard link by directly interacting with the system.

• 7 Essential Command Line Tools 2022 - YouTube
• Enter.
• Automatically run commands when given file is saved.

• Creates a named pipe, which can be accessed from multiple sessions.

• Pipe input to both standard output and a file.

• Flushes cached data.

• Octal dump. POSIX. Can be used for other bases.

• The options are given as variables format
• bs ibs obs byte size
• if of input, output files
• count skip
• conv convert while copying, status progress

Zeroes out the file and then unlink

Controls the buffer of standard input and output.

Modifies file size.

List open files

• Note that everything is a file in UNIX-like systems.
• -i list all open network connections?

tape archive

• -c create. should be used with -f to set the archive filename
• -x extract. should be used with -f to select the archive
  • It detects the compression algorithm automatically, but it can be set manually also.
  • -a --auto-compress detect the compression algorithm based on the archive suffix.
• -f select the file or filename.
• -v verbose
• filter through -z gzip , -Z compress, -j bzip2, -J xz, -I COMMAND use COMMAND.

• zip OPTIONS ARCHIVE FILES

copy in and out. It copies files between archives and directories.

• -o --create
• -i --extract
• --file
• --block-size=BLOCK-SIZE set the I/O block size
• -D --directory=DIR
• -c old portable archive format, -H --format=FORMAT use the FORMAT, the default format one is newc?
  • bin obsolete binary format
  • odc old POSIX.1 portable format
  • newc new SVR4 portable format
  • crc SVR4 format with checksum
  • tar
  • ustar
  • hpbin
  • hpodc

• NEVER lose dotfiles again with GNU Stow - YouTube
• put dotfiles in one directory, for ease of management and migration.

• Compress and decompress into and out of .webp
• dwebp WEBP -o PNG/JPG
• cwebp IMAGE -o WEBP -q [0-100]

Transform PDF files. For example, encryption and decryption, or web optimization.

• Relational SQL-like join on two text files.

• Wrap the text to a specified width.

• Paginate or columnate text for printing.

• Reverse strings.

• Shuffle input.

• Sort input.

• See

• Make each word from input unique.

• Translate(replace) single byte characters.

• Convert JPEG image to ASCII art.

• Perform set operations.
  • $ comm -12 A B
  • Flags
    • 1 : Remove elements only in the first set
    • 2 : Remove elements only in the second set
    • 3 : Remove elements in both the first and the second set

• seq <initial> <increment> <quantity>

• jq: A Practical Guide - YouTube
  • JSON Queryer

• Stream Editor
  • It processes text line by line.
• The stream version of the ed, the original UNIX text file editor, which also used similar commands.
• The structure is inherited by .

• Al *A*ho, Peter *W*einberger, Brian *K*ernighan
• The text file manipulator, powered by yacc
  • with a Scripting Language
  • The program is reimplemented under GNU project as gawk, powered by the reimplementation of yacc, bison.

• Show the entire process tree.

• Monitor the processes
  • Keybindings
    • h help
    • < > change the sorted column
    • f change the properties to display
    • Z change the color scheme
    • A toggle multi-window view
    • V toggle forest (process trees)
      • v fold a branch
    • W save this preset
    • i hide idle processes
    • c toggle full commands
    • u, o filter processes
    • Toggle: <C-p> namespaces (cgroup: , ipc: , …), <C-n> environment variables, <C-u> supplementary groups (plugdev, wheel, harry), <C-k> full commands, <C-g> control groups (0::/user.slice/…).
    • q exit

• Show the number of processors.

• Set a nice value to a program so that smaller valued ones finish faster on average.

• Show which process is using a file or a device. With -n tcp <port> flag, it shows which process is using a tcp port.

• timeout 2h <command>
  • Terminate the command based on time.

• Set environment variables for the process

• GNU Parallel
  • Execute multiple jobs of the command given in a special format, each with given arguments.
  • {} argument, {.} argument without file extension, …
  • ::: arguments, < arguments file

Print y repeatedly, so that it can be piped to another program.

Print the current environment variables.

Execute command in an existing process.

Keep the kernel, reboot the user space.

Monitor packets

from core/net-tools

dump socket statistics.

list symbols from object files

It is the media server that can host various musics. I feel like this is not a good option for personal music player.

It is a CLI tool, that has separate frontend: smplayer, etc. These tools is not well-maintained.

Audio and video player based on MPlayer, mplayer2, and FFmpeg.

• mpv-mpris ./linux.html#org1602f7c support

• It is configurable

• Animals other than cow is also available.

• Random quotes

• ASCII text stylizer

• Audio visualizer

• Screensaver

• Info
• The Art of Linux CLIs - YouTube

• Generate modem signal based on input.

• Short version of man page. It provides a quick snippets.

• Show uid, gid and others of a given user (current user if unprovided).

• Fuzzy find command.

rocm-smi-lib is required to display GPU informations.

Evaluate the expression. Each component of the expression must be separated by space, and the reserved characters must be escaped.

• String manipulation with
  • STRING : REGEXP, match STRING REGEXP, length, index, substr STRING POS LEN
• Arithmetic operation with
  • + - * / % > < = >=
  • n | m if n=0 return m; else return n, n & m if n=0 && m=0 return 0; else return n
  • Precedence is controlled by parenthesis. They need to be escaped in Bash.

• Print datetime
  • -d STRING --date=STRING use this datetime.
  • +FMT format it
  • -u --utc --universal print or set UTC
  • --rfc-3339={date|hours|minutes|seconds|ns}
  • -I --iso-8601={date|hours|minutes|seconds|ns} use ISO format

• Arbitrary precision calculator

The syntax is identical to plain C without semicolon and types. Note that semicolon is still used to separate statements in a statement list {...; ...}.

Every variable is assumed to be a number, string cannot be assigned to a variable. String must be surrounded by ".

The function is defined with the keyword define:

define [void] <name> ( <parameters> ) {
  <statements>
}

If void keyword is used the function returns nothing instead of zero (the value of print).

Some expressions are builtin.

• return (EXPR).
• length (EXPR) the number of digits before the decimal point, scale (EXPR) the number of digits after the decimal point.
• read(), scale(EXPR) the precision, sqrt(EXPR)
• print EXPR1, EXPR2, ...

With math library (-l or --mathlib), six functions are defined:

• s (x) sine (in radian)
• c (x) cosine
• a (x) arc tangent
• l (x) natural logarithm
• e (x) exponential function
• j (n,x) Bessel function

The exit keyword is quit