From 38c96e95be43fb1616437b271f32e57c1140423b Mon Sep 17 00:00:00 2001
From: Raihan Sharif <raihansharif92@gmail.com>
Date: Mon, 3 Aug 2026 13:30:34 +0100
Subject: [PATCH 01/20] set up argparse with -n, -n flags

---
 implement-shell-tools/cat/cat.py          | 14 ++++++++++++++
 implement-shell-tools/wc/requirements.txt |  1 +
 2 files changed, 15 insertions(+)
 create mode 100644 implement-shell-tools/cat/cat.py
 create mode 100644 implement-shell-tools/wc/requirements.txt

diff --git a/implement-shell-tools/cat/cat.py b/implement-shell-tools/cat/cat.py
new file mode 100644
index 000000000..2a6b69988
--- /dev/null
+++ b/implement-shell-tools/cat/cat.py
@@ -0,0 +1,14 @@
+import argparse
+
+parser = argparse.ArgumentParser(
+    prog="a simple cat implementation",
+    description="cat command line tool with the -n and -b flags"
+)
+
+parser.add_argument("-n", action="store_true", help="number all output lines")
+parser.add_argument("-b", action="store_true", help="number non-empty output lines")
+parser.add_argument("paths", nargs="+", help="file path or paths", )
+
+args = parser.parse_args();
+
+print(args)
\ No newline at end of file
diff --git a/implement-shell-tools/wc/requirements.txt b/implement-shell-tools/wc/requirements.txt
new file mode 100644
index 000000000..e9c6824d6
--- /dev/null
+++ b/implement-shell-tools/wc/requirements.txt
@@ -0,0 +1 @@
+argparse
\ No newline at end of file

From 0591f3f61428114bcf885c4905023cfeb2824aa5 Mon Sep 17 00:00:00 2001
From: Raihan Sharif <raihansharif92@gmail.com>
Date: Mon, 3 Aug 2026 13:46:54 +0100
Subject: [PATCH 02/20] handle errors when reading file

---
 implement-shell-tools/cat/cat.py | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/implement-shell-tools/cat/cat.py b/implement-shell-tools/cat/cat.py
index 2a6b69988..2335992fb 100644
--- a/implement-shell-tools/cat/cat.py
+++ b/implement-shell-tools/cat/cat.py
@@ -1,4 +1,5 @@
 import argparse
+import sys
 
 parser = argparse.ArgumentParser(
     prog="a simple cat implementation",
@@ -11,4 +12,25 @@
 
 args = parser.parse_args();
 
-print(args)
\ No newline at end of file
+# cat returns different error messages depending on the reason the path could be read
+def cat_file(path):
+    try:
+        with open(path, "r",) as f:
+            content = f.read()
+    except FileNotFoundError:
+        print(f"cat: {path}: No such file or directory", file=sys.stderr)
+        return
+    except IsADirectoryError:
+        print(f"cat: {path}: Is a directory", file=sys.stderr)
+        return
+    except PermissionError:
+        print(f"cat: {path}: Permission denied", file=sys.stderr)
+        return
+
+    print(content)
+
+
+
+for path in args.paths:
+    line_num = 1
+    cat_file(path)
\ No newline at end of file

From 6020eef11e6daee88e9631e621a729e04ffe9e06 Mon Sep 17 00:00:00 2001
From: Raihan Sharif <raihansharif92@gmail.com>
Date: Mon, 3 Aug 2026 13:55:46 +0100
Subject: [PATCH 03/20] return exit code 1 for any failed file read

---
 implement-shell-tools/cat/cat.py | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/implement-shell-tools/cat/cat.py b/implement-shell-tools/cat/cat.py
index 2335992fb..32f66cfdd 100644
--- a/implement-shell-tools/cat/cat.py
+++ b/implement-shell-tools/cat/cat.py
@@ -19,18 +19,28 @@ def cat_file(path):
             content = f.read()
     except FileNotFoundError:
         print(f"cat: {path}: No such file or directory", file=sys.stderr)
-        return
+        return False
     except IsADirectoryError:
         print(f"cat: {path}: Is a directory", file=sys.stderr)
-        return
+        return False
     except PermissionError:
         print(f"cat: {path}: Permission denied", file=sys.stderr)
-        return
+        return False
 
     print(content)
 
 
 
+# cat exits with error code 1 if any file read fails
+file_error = False
+
 for path in args.paths:
     line_num = 1
-    cat_file(path)
\ No newline at end of file
+    is_success = cat_file(path)
+
+    if not is_success:
+        file_error = True
+
+# if at any point, file reading failed file error is set to True, 
+# and program exist with code 1 after all tasks completed
+sys.exit(1 if file_error else 0)
\ No newline at end of file

From 108fef7cbe1ae35067cf1bc4db809f3dc238bde3 Mon Sep 17 00:00:00 2001
From: Raihan Sharif <raihansharif92@gmail.com>
Date: Mon, 3 Aug 2026 14:19:19 +0100
Subject: [PATCH 04/20] seperate out file read and formatting

---
 implement-shell-tools/cat/cat.py | 64 ++++++++++++++++++++++----------
 1 file changed, 45 insertions(+), 19 deletions(-)

diff --git a/implement-shell-tools/cat/cat.py b/implement-shell-tools/cat/cat.py
index 32f66cfdd..8523a7301 100644
--- a/implement-shell-tools/cat/cat.py
+++ b/implement-shell-tools/cat/cat.py
@@ -13,34 +13,60 @@
 args = parser.parse_args();
 
 # cat returns different error messages depending on the reason the path could be read
-def cat_file(path):
+def read_file(path):
+    """Returns (content, error_message). error_message is None on success"""
     try:
         with open(path, "r",) as f:
-            content = f.read()
+            return f.read(), None
     except FileNotFoundError:
-        print(f"cat: {path}: No such file or directory", file=sys.stderr)
-        return False
+        return None, f"cat: {path}: No such file or directory"
     except IsADirectoryError:
-        print(f"cat: {path}: Is a directory", file=sys.stderr)
-        return False
+        return None, f"cat: {path}: Is a directory"
     except PermissionError:
-        print(f"cat: {path}: Permission denied", file=sys.stderr)
-        return False
+        return None, f"cat: {path}: Permission denied"
 
-    print(content)
 
+# -b (number the non-empty lines) takes priority over -n (number all lines)
+# if both are present
+def format_lines(lines, number_all=False, number_non_empty=False):
+    """Returns a list of formatted output lines"""
+    output = []
+    
+    if number_non_empty:
+        line_num = 0
+        for line in lines:
+            if line == "":
+                output.append("")
+            else:
+                line_num += 1
+                # {line_num:6} right justied number, length of at least 6
+                # {some_str:6} left justifed string, length fo at least 6
+                output.append(f"{line_num:6}\t{line}")
+    elif number_all:
+        for i, line in enumerate(lines, start=1):
+            output.append(f"{i:6}\t{line}")
+    else:
+        output = lines
 
 
-# cat exits with error code 1 if any file read fails
-file_error = False
+# TODO: runner function to call read_file, and feed it into formatLines, then print
 
-for path in args.paths:
-    line_num = 1
-    is_success = cat_file(path)
+def main():
+    # cat exits with error code 1 if any file read fails
+    file_error = False
 
-    if not is_success:
-        file_error = True
+    for path in args.paths:
+        line_num = 1
+        is_success = cat_file(path)
 
-# if at any point, file reading failed file error is set to True, 
-# and program exist with code 1 after all tasks completed
-sys.exit(1 if file_error else 0)
\ No newline at end of file
+        if not is_success:
+            file_error = True
+
+    # if at any point, file reading failed file error is set to True, 
+    # and program exist with code 1 after all tasks completed
+    sys.exit(1 if file_error else 0)
+
+# ensures that main only runs when this file/module is directly executed
+# not when it is imported, for example, for automated tests
+if __name__ == "__main__":
+    main()
\ No newline at end of file

From 0c5aeb2d6be357cba8cb009176733e284cd081f6 Mon Sep 17 00:00:00 2001
From: Raihan Sharif <raihansharif92@gmail.com>
Date: Mon, 3 Aug 2026 14:41:49 +0100
Subject: [PATCH 05/20] cat function to cat the formatted lines

---
 implement-shell-tools/cat/cat.py | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/implement-shell-tools/cat/cat.py b/implement-shell-tools/cat/cat.py
index 8523a7301..b185e2471 100644
--- a/implement-shell-tools/cat/cat.py
+++ b/implement-shell-tools/cat/cat.py
@@ -28,11 +28,11 @@ def read_file(path):
 
 # -b (number the non-empty lines) takes priority over -n (number all lines)
 # if both are present
-def format_lines(lines, number_all=False, number_non_empty=False):
+def format_lines(lines, number_all=False, number_nonempty=False):
     """Returns a list of formatted output lines"""
     output = []
     
-    if number_non_empty:
+    if number_nonempty:
         line_num = 0
         for line in lines:
             if line == "":
@@ -48,8 +48,29 @@ def format_lines(lines, number_all=False, number_non_empty=False):
     else:
         output = lines
 
+    return output
+
 
 # TODO: runner function to call read_file, and feed it into formatLines, then print
+def cat_file(path, number_all=False, number_nonempty=False):
+    """
+    Calls read_file -> format_lines -> prints formatted line. 
+    Returns True if file read successfully, else returns False
+
+    If failed to read file, prints error to stderr
+    """
+    content, error = read_file(path)
+    if (error):
+        print(error, file=sys.stderr)
+        return False
+
+    # splitlines automatically trims trailing empty lines
+    lines = content.splitlines()
+    for line in format_lines(lines, number_all, number_nonempty):
+        print(line)
+
+    return True
+
 
 def main():
     # cat exits with error code 1 if any file read fails
@@ -57,7 +78,7 @@ def main():
 
     for path in args.paths:
         line_num = 1
-        is_success = cat_file(path)
+        is_success = cat_file(path, args.n, args.b)
 
         if not is_success:
             file_error = True

From 9361dde008e9ed7e78f0bb76f0b1a0df7cdfb672 Mon Sep 17 00:00:00 2001
From: Raihan Sharif <raihansharif92@gmail.com>
Date: Tue, 4 Aug 2026 22:47:46 +0100
Subject: [PATCH 06/20] remove stray semicolon

---
 implement-shell-tools/cat/cat.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/implement-shell-tools/cat/cat.py b/implement-shell-tools/cat/cat.py
index b185e2471..57ae39682 100644
--- a/implement-shell-tools/cat/cat.py
+++ b/implement-shell-tools/cat/cat.py
@@ -10,7 +10,7 @@
 parser.add_argument("-b", action="store_true", help="number non-empty output lines")
 parser.add_argument("paths", nargs="+", help="file path or paths", )
 
-args = parser.parse_args();
+args = parser.parse_args()
 
 # cat returns different error messages depending on the reason the path could be read
 def read_file(path):

From 36177423416a70edb0245cb839b1bca06695974f Mon Sep 17 00:00:00 2001
From: Raihan Sharif <raihansharif92@gmail.com>
Date: Tue, 4 Aug 2026 22:57:44 +0100
Subject: [PATCH 07/20] set up parser

---
 implement-shell-tools/ls/ls.py | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 implement-shell-tools/ls/ls.py

diff --git a/implement-shell-tools/ls/ls.py b/implement-shell-tools/ls/ls.py
new file mode 100644
index 000000000..40ab3a1ac
--- /dev/null
+++ b/implement-shell-tools/ls/ls.py
@@ -0,0 +1,23 @@
+import argparse
+import sys
+
+parser = argparse.ArgumentParser(
+    prog="a simple version of ls",
+    description="ls command line tool which can accept 0 or more arguements" \
+    "and take -a and -1 flags")
+
+parser.add_argument("-a", action="store_true", help="show all files, including dot files")
+
+# can't store as an attribute of Namespace object, because 1 is not a valid python identifier
+# but can store under the name given in the dest argument. When working with this
+# parser, look for "opt_one", not "1".
+parser.add_argument("-1", dest="opt_one", action="store_true", help="show one file/directory name per line")
+
+# takes 0 more arguments, if none are given, sets "." as default value
+parser.add_argument("paths", nargs="*", help="file/directory path(s) to display", default=".")
+
+args = parser.parse_args()
+
+print(args)
+
+# def getDirectoryEntries(path, aFlag=args.a):

From b28fa81af78f51ae003fd743ee1ecdaf2136e3e3 Mon Sep 17 00:00:00 2001
From: Raihan Sharif <raihansharif92@gmail.com>
Date: Tue, 4 Aug 2026 23:36:46 +0100
Subject: [PATCH 08/20] read files/folders in a given folder

---
 implement-shell-tools/ls/ls.py | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/implement-shell-tools/ls/ls.py b/implement-shell-tools/ls/ls.py
index 40ab3a1ac..c51152cd3 100644
--- a/implement-shell-tools/ls/ls.py
+++ b/implement-shell-tools/ls/ls.py
@@ -1,5 +1,6 @@
 import argparse
 import sys
+import os
 
 parser = argparse.ArgumentParser(
     prog="a simple version of ls",
@@ -18,6 +19,16 @@
 
 args = parser.parse_args()
 
-print(args)
 
-# def getDirectoryEntries(path, aFlag=args.a):
+def getDirectoryEntries(path, aFlag=args.a):
+    # warning: listdir() prints current directory by default
+    entries = os.listdir(path)
+    entries = [".", ".."] + entries
+    entries.sort()
+
+    if (not args.a):
+        entries = [entry for entry in entries if not entry.startswith(".")]
+    return entries
+
+for path in args.paths:
+    print(getDirectoryEntries(path))

From 4f62b37e13fad7e42421579589304ea235b01e0d Mon Sep 17 00:00:00 2001
From: Raihan Sharif <raihansharif92@gmail.com>
Date: Wed, 5 Aug 2026 00:02:13 +0100
Subject: [PATCH 09/20] function to format and print a single directory content

---
 implement-shell-tools/ls/ls.py | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/implement-shell-tools/ls/ls.py b/implement-shell-tools/ls/ls.py
index c51152cd3..3ca92d2f6 100644
--- a/implement-shell-tools/ls/ls.py
+++ b/implement-shell-tools/ls/ls.py
@@ -28,7 +28,19 @@ def getDirectoryEntries(path, aFlag=args.a):
 
     if (not args.a):
         entries = [entry for entry in entries if not entry.startswith(".")]
+        
     return entries
 
+def printEntries(entries, onePerLineFlag = args.opt_one):
+    if (onePerLineFlag):
+        for entry in entries:
+            print(entry)
+    else:
+        for i in range(len(entries)-1):
+            print(f"{entries[i]}\t", end="")
+        print(entries[-1])
+
+
+
 for path in args.paths:
-    print(getDirectoryEntries(path))
+    printEntries(getDirectoryEntries(path))

From 2ad95a6a25524a0c4f609f5f46da4f8d8a63be72 Mon Sep 17 00:00:00 2001
From: Raihan Sharif <raihansharif92@gmail.com>
Date: Wed, 5 Aug 2026 00:17:37 +0100
Subject: [PATCH 10/20] snake case function names

---
 implement-shell-tools/ls/ls.py | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/implement-shell-tools/ls/ls.py b/implement-shell-tools/ls/ls.py
index 3ca92d2f6..1afba00d5 100644
--- a/implement-shell-tools/ls/ls.py
+++ b/implement-shell-tools/ls/ls.py
@@ -20,7 +20,7 @@
 args = parser.parse_args()
 
 
-def getDirectoryEntries(path, aFlag=args.a):
+def get_dir_entries(path, aFlag=args.a):
     # warning: listdir() prints current directory by default
     entries = os.listdir(path)
     entries = [".", ".."] + entries
@@ -28,10 +28,10 @@ def getDirectoryEntries(path, aFlag=args.a):
 
     if (not args.a):
         entries = [entry for entry in entries if not entry.startswith(".")]
-        
+
     return entries
 
-def printEntries(entries, onePerLineFlag = args.opt_one):
+def print_entries(entries, onePerLineFlag = args.opt_one):
     if (onePerLineFlag):
         for entry in entries:
             print(entry)
@@ -41,6 +41,5 @@ def printEntries(entries, onePerLineFlag = args.opt_one):
         print(entries[-1])
 
 
-
-for path in args.paths:
-    printEntries(getDirectoryEntries(path))
+# for path in args.paths:
+#     printEntries(getDirectoryEntries(path))

From 36c79a6e3793977222b9166e233e0ba92a508fd1 Mon Sep 17 00:00:00 2001
From: Raihan Sharif <raihansharif92@gmail.com>
Date: Wed, 5 Aug 2026 00:35:02 +0100
Subject: [PATCH 11/20] print multiple files and folders

---
 implement-shell-tools/ls/ls.py | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/implement-shell-tools/ls/ls.py b/implement-shell-tools/ls/ls.py
index 1afba00d5..0a614e6cf 100644
--- a/implement-shell-tools/ls/ls.py
+++ b/implement-shell-tools/ls/ls.py
@@ -31,15 +31,32 @@ def get_dir_entries(path, aFlag=args.a):
 
     return entries
 
+
 def print_entries(entries, onePerLineFlag = args.opt_one):
     if (onePerLineFlag):
         for entry in entries:
             print(entry)
-    else:
+    elif (len(entries) > 0):
         for i in range(len(entries)-1):
             print(f"{entries[i]}\t", end="")
-        print(entries[-1])
+        print(f"{entries[-1]}")
+
+
+def main():
+    # file and directory paths are processed separately
+    file_args = [arg for arg in args.paths if os.path.isfile(arg)]
+    dir_args = [arg for arg in args.paths if os.path.isdir(arg)]
+
+    if (len(file_args) > 0):
+        print_entries(file_args)
+
+    for index, path in enumerate(dir_args, start=0):
+        if (len(args.paths) > 1):
+            if (index > 0 or len(file_args) > 0):
+                print("")
+            print(f"{path}:")
+        print_entries(get_dir_entries(path))
 
 
-# for path in args.paths:
-#     printEntries(getDirectoryEntries(path))
+if __name__ == "__main__":
+    main()
\ No newline at end of file

From 34e629a847a706d8a48949655a8f95e0d0780d9e Mon Sep 17 00:00:00 2001
From: Raihan Sharif <raihansharif92@gmail.com>
Date: Wed, 5 Aug 2026 00:52:57 +0100
Subject: [PATCH 12/20] add very basic error handling

all paths that are not accessible as a file/folder throw same error
---
 implement-shell-tools/ls/ls.py | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/implement-shell-tools/ls/ls.py b/implement-shell-tools/ls/ls.py
index 0a614e6cf..d1dab65ad 100644
--- a/implement-shell-tools/ls/ls.py
+++ b/implement-shell-tools/ls/ls.py
@@ -44,8 +44,26 @@ def print_entries(entries, onePerLineFlag = args.opt_one):
 
 def main():
     # file and directory paths are processed separately
-    file_args = [arg for arg in args.paths if os.path.isfile(arg)]
-    dir_args = [arg for arg in args.paths if os.path.isdir(arg)]
+    # file_args = [arg for arg in args.paths if os.path.isfile(arg)]
+    # dir_args = [arg for arg in args.paths if os.path.isdir(arg)]
+
+    file_args = []
+    dir_args = []
+    invalid_args = []
+
+    # this is a simplication, it groups all errors under "invalid file"
+    # real ls would have different messages things like permission denied
+    # also bad because it makes two syscalls
+    for arg in args.paths:
+        if (os.path.isfile(arg)):
+            file_args.append(arg)
+        elif (os.path.isdir(arg)):
+            dir_args.append(arg)
+        else:
+            invalid_args.append(arg)
+
+    for arg in invalid_args:
+        print(f"ls: {arg}: No such file or directory", file=sys.stderr)
 
     if (len(file_args) > 0):
         print_entries(file_args)

From 2d9a74081bdb5e4d54c28fa95244850a4b4d1615 Mon Sep 17 00:00:00 2001
From: Raihan Sharif <raihansharif92@gmail.com>
Date: Wed, 5 Aug 2026 12:01:38 +0100
Subject: [PATCH 13/20] add a requirements file for argparse import

---
 implement-shell-tools/ls/requirements.txt | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 implement-shell-tools/ls/requirements.txt

diff --git a/implement-shell-tools/ls/requirements.txt b/implement-shell-tools/ls/requirements.txt
new file mode 100644
index 000000000..e9c6824d6
--- /dev/null
+++ b/implement-shell-tools/ls/requirements.txt
@@ -0,0 +1 @@
+argparse
\ No newline at end of file

From ef611c61a9569bbd465e264599f819febd78d134 Mon Sep 17 00:00:00 2001
From: Raihan Sharif <raihansharif92@gmail.com>
Date: Wed, 5 Aug 2026 12:29:04 +0100
Subject: [PATCH 14/20] parser setup

---
 implement-shell-tools/wc/wc.py | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
 create mode 100644 implement-shell-tools/wc/wc.py

diff --git a/implement-shell-tools/wc/wc.py b/implement-shell-tools/wc/wc.py
new file mode 100644
index 000000000..de9f9c946
--- /dev/null
+++ b/implement-shell-tools/wc/wc.py
@@ -0,0 +1,15 @@
+import argparse
+import sys
+import os
+
+parser = argparse.ArgumentParser(
+    prog="a simple version of wc. Takes in one or more files.",
+    description="ls command line tool which can accept -l -w -c cflags")
+
+parser.add_argument("-l", action="store_true", help="show line count")
+parser.add_argument("-w", action="store_true", help="show word count")
+parser.add_argument("-c", action="store_true", help="show byte count")
+
+parser.add_argument("paths", nargs="*", help="file(s) for which to show data")
+
+args = parser.parse_args()
\ No newline at end of file

From 575f0bf1f9ff92e3cc52be7cd43521474824e730 Mon Sep 17 00:00:00 2001
From: Raihan Sharif <raihansharif92@gmail.com>
Date: Wed, 5 Aug 2026 14:23:48 +0100
Subject: [PATCH 15/20] logic completed

---
 implement-shell-tools/wc/wc.py | 67 ++++++++++++++++++++++++++++++++--
 1 file changed, 63 insertions(+), 4 deletions(-)

diff --git a/implement-shell-tools/wc/wc.py b/implement-shell-tools/wc/wc.py
index de9f9c946..d5aec9e01 100644
--- a/implement-shell-tools/wc/wc.py
+++ b/implement-shell-tools/wc/wc.py
@@ -6,10 +6,69 @@
     prog="a simple version of wc. Takes in one or more files.",
     description="ls command line tool which can accept -l -w -c cflags")
 
-parser.add_argument("-l", action="store_true", help="show line count")
-parser.add_argument("-w", action="store_true", help="show word count")
-parser.add_argument("-c", action="store_true", help="show byte count")
+parser.add_argument("-l", action="store_true", help="show line count", default="l")
+parser.add_argument("-w", action="store_true", help="show word count", default='w')
+parser.add_argument("-c", action="store_true", help="show byte count", default="c")
 
 parser.add_argument("paths", nargs="*", help="file(s) for which to show data")
 
-args = parser.parse_args()
\ No newline at end of file
+args = parser.parse_args()
+
+totals = {"l": 0, "w": 0, "c": 0}
+
+file_count = 0
+
+for path in args.paths:
+    try:
+        if (os.path.isdir(path)):
+            print(f"wc: {path}: read: Is a directory")
+    except:
+        print(f"wc: {path} open: No such file or directory", file=sys.stderr)
+        file_count += 1
+        continue
+
+    if (os.path.isfile(path)):
+        file_count += 1
+        output_str = ""
+
+        with open(path, "r", encoding="utf-8") as file:
+            lines = file.readlines()
+
+            if (args.l):
+                if (len(lines) > 0 and lines[-1] == ""):
+                    lines.pop()
+
+                line_count = len(lines)
+                totals["l"] += line_count
+                output_str += f"\t{line_count}"
+
+            if (args.w):
+                word_count = 0
+                for line in lines:
+                    # python string.split splits on any white space
+                    word_count += len(line.split())
+                totals["w"] += word_count
+                output_str += f"\t{word_count}"
+
+            if (args.c):
+                bytes = os.path.getsize(path)
+                totals["c"] += bytes
+                output_str += f"\t{bytes}"
+
+        output_str += f" {path}"
+        print(output_str)
+
+if (file_count > 1):
+    res = {key : val for key, val in totals.items() 
+           if val != 0}
+    total_str = ""
+    for v in res.values():
+        total_str += f"\t{v}"
+
+    total_str += " total"
+    print(total_str)
+            
+
+                
+
+

From 87d8179e9a98ffd31ac49397206b41c8ec2c243c Mon Sep 17 00:00:00 2001
From: Raihan Sharif <raihansharif92@gmail.com>
Date: Wed, 5 Aug 2026 14:37:09 +0100
Subject: [PATCH 16/20] wc formatting matches real formatting exactly.

---
 implement-shell-tools/wc/wc.py | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/implement-shell-tools/wc/wc.py b/implement-shell-tools/wc/wc.py
index d5aec9e01..3d0c24dcf 100644
--- a/implement-shell-tools/wc/wc.py
+++ b/implement-shell-tools/wc/wc.py
@@ -2,6 +2,8 @@
 import sys
 import os
 
+# TODO: decompose into functions to make it more modular and reusable
+
 parser = argparse.ArgumentParser(
     prog="a simple version of wc. Takes in one or more files.",
     description="ls command line tool which can accept -l -w -c cflags")
@@ -40,7 +42,7 @@
 
                 line_count = len(lines)
                 totals["l"] += line_count
-                output_str += f"\t{line_count}"
+                output_str += f"{line_count:8}"
 
             if (args.w):
                 word_count = 0
@@ -48,12 +50,12 @@
                     # python string.split splits on any white space
                     word_count += len(line.split())
                 totals["w"] += word_count
-                output_str += f"\t{word_count}"
+                output_str += f"{word_count:8}"
 
             if (args.c):
                 bytes = os.path.getsize(path)
                 totals["c"] += bytes
-                output_str += f"\t{bytes}"
+                output_str += f"{bytes:8}"
 
         output_str += f" {path}"
         print(output_str)
@@ -63,7 +65,7 @@
            if val != 0}
     total_str = ""
     for v in res.values():
-        total_str += f"\t{v}"
+        total_str += f"{v:8}"
 
     total_str += " total"
     print(total_str)

From 4995bfc099ef9a02822cc7dba5e0fb1bcced4116 Mon Sep 17 00:00:00 2001
From: Raihan Sharif <raihansharif92@gmail.com>
Date: Wed, 5 Aug 2026 14:38:48 +0100
Subject: [PATCH 17/20] add utf-8 encoding to cat

---
 implement-shell-tools/cat/cat.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/implement-shell-tools/cat/cat.py b/implement-shell-tools/cat/cat.py
index 57ae39682..16fb42367 100644
--- a/implement-shell-tools/cat/cat.py
+++ b/implement-shell-tools/cat/cat.py
@@ -16,7 +16,7 @@
 def read_file(path):
     """Returns (content, error_message). error_message is None on success"""
     try:
-        with open(path, "r",) as f:
+        with open(path, "r", encoding="utf-8") as f:
             return f.read(), None
     except FileNotFoundError:
         return None, f"cat: {path}: No such file or directory"

From 0e5e2ee7b7d84663aaf4bc531def6ad71a8340d3 Mon Sep 17 00:00:00 2001
From: Raihan Sharif <raihansharif92@gmail.com>
Date: Wed, 5 Aug 2026 14:47:31 +0100
Subject: [PATCH 18/20] no need to keep track of file count

---
 implement-shell-tools/wc/wc.py | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/implement-shell-tools/wc/wc.py b/implement-shell-tools/wc/wc.py
index 3d0c24dcf..d31796cda 100644
--- a/implement-shell-tools/wc/wc.py
+++ b/implement-shell-tools/wc/wc.py
@@ -18,8 +18,6 @@
 
 totals = {"l": 0, "w": 0, "c": 0}
 
-file_count = 0
-
 for path in args.paths:
     try:
         if (os.path.isdir(path)):
@@ -30,7 +28,6 @@
         continue
 
     if (os.path.isfile(path)):
-        file_count += 1
         output_str = ""
 
         with open(path, "r", encoding="utf-8") as file:
@@ -60,7 +57,7 @@
         output_str += f" {path}"
         print(output_str)
 
-if (file_count > 1):
+if (len(args.paths) > 1):
     res = {key : val for key, val in totals.items() 
            if val != 0}
     total_str = ""

From 1ea4d3e37bb2b020c35d9f0ff1ab65a63360cc12 Mon Sep 17 00:00:00 2001
From: Raihan Sharif <raihansharif92@gmail.com>
Date: Wed, 5 Aug 2026 15:00:50 +0100
Subject: [PATCH 19/20] correctly print error message

---
 implement-shell-tools/wc/wc.py | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/implement-shell-tools/wc/wc.py b/implement-shell-tools/wc/wc.py
index d31796cda..b6ce983a3 100644
--- a/implement-shell-tools/wc/wc.py
+++ b/implement-shell-tools/wc/wc.py
@@ -19,17 +19,12 @@
 totals = {"l": 0, "w": 0, "c": 0}
 
 for path in args.paths:
-    try:
-        if (os.path.isdir(path)):
-            print(f"wc: {path}: read: Is a directory")
-    except:
-        print(f"wc: {path} open: No such file or directory", file=sys.stderr)
-        file_count += 1
-        continue
-
-    if (os.path.isfile(path)):
+    if (not os.path.exists(path)):
+        print(f"wc: {path}: open: No such file or directory", file=sys.stderr)
+    elif (os.path.isdir(path)):
+        print(f"wc: {path}: read: Is a directory") 
+    elif (os.path.isfile(path)):
         output_str = ""
-
         with open(path, "r", encoding="utf-8") as file:
             lines = file.readlines()
 

From 085a1ac4945038adb4961006a0d6ea1a4f14ab22 Mon Sep 17 00:00:00 2001
From: Raihan Sharif <raihansharif92@gmail.com>
Date: Thu, 6 Aug 2026 11:44:22 +0100
Subject: [PATCH 20/20] implement changes from code review

---
 implement-shell-tools/ls/requirements.txt |  1 -
 implement-shell-tools/wc/requirements.txt |  1 -
 implement-shell-tools/wc/wc.py            | 27 +++++++++++++----------
 3 files changed, 15 insertions(+), 14 deletions(-)
 delete mode 100644 implement-shell-tools/ls/requirements.txt
 delete mode 100644 implement-shell-tools/wc/requirements.txt

diff --git a/implement-shell-tools/ls/requirements.txt b/implement-shell-tools/ls/requirements.txt
deleted file mode 100644
index e9c6824d6..000000000
--- a/implement-shell-tools/ls/requirements.txt
+++ /dev/null
@@ -1 +0,0 @@
-argparse
\ No newline at end of file
diff --git a/implement-shell-tools/wc/requirements.txt b/implement-shell-tools/wc/requirements.txt
deleted file mode 100644
index e9c6824d6..000000000
--- a/implement-shell-tools/wc/requirements.txt
+++ /dev/null
@@ -1 +0,0 @@
-argparse
\ No newline at end of file
diff --git a/implement-shell-tools/wc/wc.py b/implement-shell-tools/wc/wc.py
index b6ce983a3..43dec21df 100644
--- a/implement-shell-tools/wc/wc.py
+++ b/implement-shell-tools/wc/wc.py
@@ -8,9 +8,9 @@
     prog="a simple version of wc. Takes in one or more files.",
     description="ls command line tool which can accept -l -w -c cflags")
 
-parser.add_argument("-l", action="store_true", help="show line count", default="l")
-parser.add_argument("-w", action="store_true", help="show word count", default='w')
-parser.add_argument("-c", action="store_true", help="show byte count", default="c")
+parser.add_argument("-l", action="store_true", help="show line count")
+parser.add_argument("-w", action="store_true", help="show word count")
+parser.add_argument("-c", action="store_true", help="show byte count")
 
 parser.add_argument("paths", nargs="*", help="file(s) for which to show data")
 
@@ -18,29 +18,32 @@
 
 totals = {"l": 0, "w": 0, "c": 0}
 
+# if no flags then set all flags to true, same as in real wc
+if (not args.l and not args.w and not args.c):
+    args.l = args.w = args.c = True
+
 for path in args.paths:
     if (not os.path.exists(path)):
         print(f"wc: {path}: open: No such file or directory", file=sys.stderr)
     elif (os.path.isdir(path)):
-        print(f"wc: {path}: read: Is a directory") 
+        print(f"wc: {path}: read: Is a directory", file=sys.stderr) 
     elif (os.path.isfile(path)):
         output_str = ""
         with open(path, "r", encoding="utf-8") as file:
-            lines = file.readlines()
+            content = file.read()
 
+            lines = content.split('\n')
+            
             if (args.l):
-                if (len(lines) > 0 and lines[-1] == ""):
-                    lines.pop()
+                #if (len(lines)) > 0: 
+                 #   lines[-1].strip()
 
-                line_count = len(lines)
+                line_count = content.count('\n')
                 totals["l"] += line_count
                 output_str += f"{line_count:8}"
 
             if (args.w):
-                word_count = 0
-                for line in lines:
-                    # python string.split splits on any white space
-                    word_count += len(line.split())
+                word_count = len(content.split())
                 totals["w"] += word_count
                 output_str += f"{word_count:8}"