utilities

Makefile

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+CC=cc
+CFLAGS=-I include/ -I lib/ -Wall -Werror
+RM=rm -f
+
+all: libraries programs
+
+cleanall: clean cleanlibraries cleanprograms
+
+clean:
+	$(RM) src/*.o
+
+cleanlibraries:
+	$(RM) lib/libshell.o
+	$(RM) lib/libstr.o
+
+cleanprograms:
+	$(RM) bin/add
+	$(RM) bin/cut
+	$(RM) bin/echo
+	$(RM) bin/eq
+	$(RM) bin/false
+	$(RM) bin/fdivide
+	$(RM) bin/gt
+	$(RM) bin/lowercase
+	$(RM) bin/lt
+	$(RM) bin/mm
+	$(RM) bin/multiply
+	$(RM) bin/nonzero
+	$(RM) bin/simexec
+	$(RM) bin/sleep
+	$(RM) bin/streq
+	$(RM) bin/stris
+	$(RM) bin/substitute
+	$(RM) bin/tail
+
+libraries: libshell libstr stdbool sysexits
+
+libshell: lib/libshell.c lib/libshell.h
+	$(CC) $(CFLAGS) -o lib/libshell.o -c lib/libshell.c
+
+libstr: lib/libstr.c lib/libstr.h
+	$(CC) $(CFLAGS) -o lib/libstr.o -c lib/libstr.c
+
+stdbool: include/stdbool.h
+
+sysexits: src/sysexits.c
+	$(CC) $(CFLAGS) -o bin/sysexits src/sysexits.c
+	bin/sysexits >include/sysexits.h
+
+programs: echo false nonzero simexec sleep streq stris
+
+calculate: libstr sysexits src/calculate.c
+	$(CC) $(CFLAGS) -o src/calculate.o -c src/calculate.c
+	$(CC) $(CFLAGS) -o bin/calculate lib/libstr.o src/calculate.o
+
+echo: sysexits src/echo.c
+	$(CC) $(CFLAGS) -o bin/echo src/echo.c
+
+false: src/false.c
+	$(CC) $(CFLAGS) -o bin/false src/false.c
+
+id: stdbool sysexits src/id.c
+	$(CC) $(CFLAGS) -o bin/id src/id.c
+
+levenshtein: src/levenshtein.c
+	$(CC) $(CFLAGS) -o bin/levenshtein src/levenshtein.c
+
+lowercase: sysexits src/lowercase.c
+	$(CC) $(CFLAGS) -o bin/lowercase src/lowercase.c
+
+nonzero: src/nonzero.c
+	$(CC) $(CFLAGS) -o bin/nonzero src/nonzero.c
+
+runlength: noargvzero sysexits src/runlength.c
+	$(CC) $(CFLAGS) -o bin/runlength src/runlength.c
+
+simexec: noargvzero sysexits src/simexec.c
+	$(CC) $(CFLAGS) -o bin/simexec src/simexec.c
+
+streq: noargvzero sysexits src/streq.c
+	$(CC) $(CFLAGS) -o bin/streq src/streq.c
+
+stris: libstr src/stris.c
+	$(CC) $(CFLAGS) -c -o src/stris.o src/stris.c
+	$(CC) $(CFLAGS) -o bin/stris lib/libstr.o src/stris.o
+
+sleep: libstr noargvzero sysexits src/sleep.c
+	$(CC) $(CFLAGS) -c -o src/sleep.o src/sleep.c
+	$(CC) $(CFLAGS) -o bin/sleep lib/libstr.o src/sleep.o
+
+substitute: stdbool src/substitute.c
+	$(CC) $(CFLAGS) -c -o src/substitute.o src/substitute.c
+	$(CC) $(CFLAGS) -o bin/substitute src/substitute.o
+
+which: libshell src/which.c
+	$(CC) $(CFLAGS) -c -o src/which.o src/which.c
+	$(CC) $(CFLAGS) -o bin/which lib/libshell.o src/which.o
+
+.PHONY: all clean cleanlibraries cleanprograms noargvzero stdbool sysexits

man/utilities.md

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+# utilities
+
+This project seeks to replicate all standard system utilities on UNIX-like system, implementing the features defined in [POSIX.1-2017](https://pubs.opengroup.org/onlinepubs/9699919799/).
+Much of this project's layout is opinionated.
+
+For a user installation, place `PATH="$HOME/bin/:"$PATH` in your `$HOME/.bashrc`, `mkdir -p $HOME/bin`, and then copy the desired utilities into that binaries folder.
+(Yes, this doesn't work for all system configurations (it doesn't work for mine), but it works for nearly all configurations beginners would have; if you know what you're doing you don't have to refer to this).
+This doesn't require root permissions and you can bypass these utilities with `/bin/[desired utility]`.
+
+System-wide installation of these utilities isn't recommended whatsoever.
+
+## building
+
+You can just read the Makefile, it's a pretty simple one.
+
+`make cleanall` - cleans
+
+`make programs` - builds all stable utilities
+
+`make [utility]` - builds a specific utility
+
+It's not necessary to `make libraries` as the Makefile knows on which libraries each program depends and will build those specific libraries when needed.
+
+## included utilities
+
+All not mentioned in this README have proper manual pages provided in `man/`.
+
+### abs
+
+Not in POSIX.
+Shellscript that returns the absolute value of an integer argument.
+Relies on *eq*(1), *lt*(1), *multiply*(1), *printf*(1), and *stris*(1).
+
+### ++
+
+Shellscript that sums 1 with the first argument using *add*(1).
+
+### --
+
+Shellscript that subtracts 1 from the first argument using *subtract*(1).
+
+### subtract
+
+Shellscript that subtracts the second argument from the first.
+Relies on *add*(1), *eq*(1), *multiply*(1), *printf*(1), and *stris*(1).
+
+### cat
+
+*cat*(1) written in POSIX shell.
+Relies on *dd*(1) and *test*(1).
+
+### eq
+
+Compares integer arguments and exits with 0 if they're all equal or 1 if some aren't equal.
+Equivalent to `test -eq`.
+
+### fdivide
+
+Not in POSIX.
+Performs **floor division** on two **integers**.
+This does not, as the name suggests, divide floating-point numbers.
+
+### gt
+
+Compares integer arguments and exits with 0 if the arguments are arranged in descending order.
+Exits with 1 if an argument is equal or greater to a previous argument.
+Equivalent to `test -gt`.
+
+### head
+
+An implementation of *head*(1) written in POSIX shell.
+Relies on *cat*(1), *printf*(1), *sed*(1), and *stris*(1).
+WIP.
+
+### lt
+
+Compares integer arguments and exits with 0 if the arguments are arranged in ascending order.
+Exits with 1 if an argument is equal or lesser to a previous argument.
+Equivalent to `test -lt`.
+
+### man
+
+Barebones implementation of *man*(1) written in POSIX shell.
+
+### mod
+
+Not in POSIX.
+Prints the remainder of the first argument divided by the second to stdout.
+Written in POSIX shell, relies on *eq*(1), *fdivide*(1), *multiply*(1), *printf*(1), *subtract*(1), *stris*(1).
+
+### tail
+
+An implementation of *tail*(1). WIP.