From 53fa60024ad7607bc039228406a1aa81b0deeff7 Mon Sep 17 00:00:00 2001
From: zohrehKazemianpour
 <129424353+zohrehKazemianpour@users.noreply.github.com>
Date: Sun, 23 Nov 2025 14:44:31 +0000
Subject: [PATCH 01/11] Add prep to gitignore

---
 .gitignore | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.gitignore b/.gitignore
index 3c3629e6..cc8b5568 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 node_modules
+prep/

From 6a33a5e5f786f565b02cd66b097fad7e55b20d89 Mon Sep 17 00:00:00 2001
From: zohrehKazemianpour
 <129424353+zohrehKazemianpour@users.noreply.github.com>
Date: Sun, 23 Nov 2025 19:37:42 +0000
Subject: [PATCH 02/11] Implement basic cat command in Python

---
 implement-shell-tools/cat/cat.py | 8 ++++++++
 1 file changed, 8 insertions(+)
 create mode 100644 implement-shell-tools/cat/cat.py

diff --git a/implement-shell-tools/cat/cat.py b/implement-shell-tools/cat/cat.py
new file mode 100644
index 00000000..757c15e0
--- /dev/null
+++ b/implement-shell-tools/cat/cat.py
@@ -0,0 +1,8 @@
+import sys
+
+filename = sys.argv[1]
+                
+with open(filename, "r") as f: 
+    content = f.read()   
+
+print(content)

From d1c13548d71817726d2972fbedcb8e2e380c938a Mon Sep 17 00:00:00 2001
From: zohrehKazemianpour
 <129424353+zohrehKazemianpour@users.noreply.github.com>
Date: Sun, 23 Nov 2025 20:25:29 +0000
Subject: [PATCH 03/11] Add -n flag to number lines in cat command

---
 implement-shell-tools/cat/cat.py | 33 ++++++++++++++++++++++++++++----
 1 file changed, 29 insertions(+), 4 deletions(-)

diff --git a/implement-shell-tools/cat/cat.py b/implement-shell-tools/cat/cat.py
index 757c15e0..0b4a7943 100644
--- a/implement-shell-tools/cat/cat.py
+++ b/implement-shell-tools/cat/cat.py
@@ -1,8 +1,33 @@
 import sys
+import argparse
 
-filename = sys.argv[1]
+# Setup argument parser
+parser = argparse.ArgumentParser(
+    prog="cat",
+    description="Concatenate and display files"
+)
+
+parser.add_argument("-n", "--number", action="store_true", help="Number all output lines")
+parser.add_argument("path", help="File to read")
+
+args = parser.parse_args()
+
+
+# Read the file 
+with open(args.path, "r") as f: 
+    content = f.read()
                 
-with open(filename, "r") as f: 
-    content = f.read()   
 
-print(content)
+# Check if numbering is needed
+if args.number:
+    lines = content.split("\n")
+    numbered_lines = []
+    
+    for index, line in enumerate(lines):
+        line_number = index + 1
+        numbered_line = f"{line_number:6}\t{line}"  # Format with tab like real cat
+        numbered_lines.append(numbered_line)
+    
+    print("\n".join(numbered_lines))
+else:
+    print(content)

From 6607cde2b1ccddbde7c5037d76cbdfd0b682e2d0 Mon Sep 17 00:00:00 2001
From: zohrehKazemianpour
 <129424353+zohrehKazemianpour@users.noreply.github.com>
Date: Sun, 23 Nov 2025 20:42:14 +0000
Subject: [PATCH 04/11] Add -b flag to number only non-empty lines

---
 implement-shell-tools/cat/cat.py | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/implement-shell-tools/cat/cat.py b/implement-shell-tools/cat/cat.py
index 0b4a7943..8f08038a 100644
--- a/implement-shell-tools/cat/cat.py
+++ b/implement-shell-tools/cat/cat.py
@@ -8,11 +8,11 @@
 )
 
 parser.add_argument("-n", "--number", action="store_true", help="Number all output lines")
+parser.add_argument("-b", "--number-nonblank", action="store_true", help="Number non-empty lines only")
 parser.add_argument("path", help="File to read")
 
 args = parser.parse_args()
 
-
 # Read the file 
 with open(args.path, "r") as f: 
     content = f.read()
@@ -29,5 +29,21 @@
         numbered_lines.append(numbered_line)
     
     print("\n".join(numbered_lines))
+
+elif args.number_nonblank:
+    lines = content.split("\n")
+    numbered_lines = []
+    line_number = 0
+    
+    for line in lines:
+        if line.strip() == "":  # Empty line
+            numbered_lines.append(line)  # Don't number it
+        else:  # Non-empty line
+            line_number = line_number + 1
+            numbered_line = f"{line_number:6}\t{line}"
+            numbered_lines.append(numbered_line)
+    
+    print("\n".join(numbered_lines))    
+    
 else:
     print(content)

From d1ed6cac71e6c2a935220cac8259d57f294b106d Mon Sep 17 00:00:00 2001
From: zohrehKazemianpour
 <129424353+zohrehKazemianpour@users.noreply.github.com>
Date: Sun, 23 Nov 2025 21:20:46 +0000
Subject: [PATCH 05/11] Add support for multiple files in cat command

---
 implement-shell-tools/cat/cat.py | 59 ++++++++++++++++----------------
 1 file changed, 30 insertions(+), 29 deletions(-)

diff --git a/implement-shell-tools/cat/cat.py b/implement-shell-tools/cat/cat.py
index 8f08038a..108678d9 100644
--- a/implement-shell-tools/cat/cat.py
+++ b/implement-shell-tools/cat/cat.py
@@ -9,41 +9,42 @@
 
 parser.add_argument("-n", "--number", action="store_true", help="Number all output lines")
 parser.add_argument("-b", "--number-nonblank", action="store_true", help="Number non-empty lines only")
-parser.add_argument("path", help="File to read")
+parser.add_argument("paths", nargs='+', help="Files to read")
 
 args = parser.parse_args()
 
-# Read the file 
-with open(args.path, "r") as f: 
-    content = f.read()
-                
+line_number = 0  # Shared counter across all files
 
-# Check if numbering is needed
-if args.number:
-    lines = content.split("\n")
-    numbered_lines = []
+# Process each file
+for path in args.paths:  # LEVEL 1: for loop starts
+    with open(path, "r") as f:  # LEVEL 2: inside for loop
+        content = f.read()  # LEVEL 3: inside with block
     
-    for index, line in enumerate(lines):
-        line_number = index + 1
-        numbered_line = f"{line_number:6}\t{line}"  # Format with tab like real cat
-        numbered_lines.append(numbered_line)
-    
-    print("\n".join(numbered_lines))
-
-elif args.number_nonblank:
-    lines = content.split("\n")
-    numbered_lines = []
-    line_number = 0
-    
-    for line in lines:
-        if line.strip() == "":  # Empty line
-            numbered_lines.append(line)  # Don't number it
-        else:  # Non-empty line
-            line_number = line_number + 1
+    # Check if numbering is needed
+    if args.number:  # LEVEL 2: inside for loop
+        lines = content.split("\n")  # LEVEL 3: inside if
+        numbered_lines = []
+        
+        for index, line in enumerate(lines):  # LEVEL 3: inside if
+            line_number = line_number + 1  # LEVEL 4: inside inner for
             numbered_line = f"{line_number:6}\t{line}"
             numbered_lines.append(numbered_line)
+        
+        print("\n".join(numbered_lines))  # LEVEL 3: inside if
     
-    print("\n".join(numbered_lines))    
+    elif args.number_nonblank:  # LEVEL 2: inside for loop
+        lines = content.split("\n")  # LEVEL 3: inside elif
+        numbered_lines = []
+        
+        for line in lines:  # LEVEL 3: inside elif
+            if line.strip() == "":  # LEVEL 4: inside inner for
+                numbered_lines.append(line)
+            else:
+                line_number = line_number + 1
+                numbered_line = f"{line_number:6}\t{line}"
+                numbered_lines.append(numbered_line)
+        
+        print("\n".join(numbered_lines))
     
-else:
-    print(content)
+    else:  # LEVEL 2: inside for loop
+        print(content)  # LEVEL 3: inside else
\ No newline at end of file

From ba64d2860fdca19fa71f457794a1a36f00c85f2e Mon Sep 17 00:00:00 2001
From: zohrehKazemianpour
 <129424353+zohrehKazemianpour@users.noreply.github.com>
Date: Sun, 23 Nov 2025 22:31:34 +0000
Subject: [PATCH 06/11] implement ls-1 command

---
 implement-shell-tools/ls/ls.py | 20 ++++++++++++++++++++
 1 file changed, 20 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 00000000..613cd5a4
--- /dev/null
+++ b/implement-shell-tools/ls/ls.py
@@ -0,0 +1,20 @@
+import os
+import argparse
+
+# Setup argument parser
+parser = argparse.ArgumentParser(
+    prog="ls",
+    description="Lists contents of a directory"
+)
+
+parser.add_argument("-1", dest="one_column", action="store_true", help="List one file per line")
+parser.add_argument("path", nargs='?', default=".", help="Directory to list (default: current directory)")
+
+args = parser.parse_args()
+
+# List directory contents
+files = os.listdir(args.path)
+
+# Print each file
+for file in files:
+    print(file)
\ No newline at end of file

From 37c7132ffae6e6ace1feb1404518dcd516b35017 Mon Sep 17 00:00:00 2001
From: zohrehKazemianpour
 <129424353+zohrehKazemianpour@users.noreply.github.com>
Date: Sun, 23 Nov 2025 22:37:23 +0000
Subject: [PATCH 07/11] Add -a flag to ls to show hidden files

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

diff --git a/implement-shell-tools/ls/ls.py b/implement-shell-tools/ls/ls.py
index 613cd5a4..c99aaea3 100644
--- a/implement-shell-tools/ls/ls.py
+++ b/implement-shell-tools/ls/ls.py
@@ -8,6 +8,7 @@
 )
 
 parser.add_argument("-1", dest="one_column", action="store_true", help="List one file per line")
+parser.add_argument("-a", "--all", action="store_true", help="Include hidden files")
 parser.add_argument("path", nargs='?', default=".", help="Directory to list (default: current directory)")
 
 args = parser.parse_args()
@@ -15,6 +16,9 @@
 # List directory contents
 files = os.listdir(args.path)
 
-# Print each file
+# Filter out hidden files unless -a flag is used
+if not args.all:
+    files = [f for f in files if not f.startswith('.')]
+
 for file in files:
     print(file)
\ No newline at end of file

From 5d1476bb17005a7e926656daecaf6d5d4817f698 Mon Sep 17 00:00:00 2001
From: zohrehKazemianpour
 <129424353+zohrehKazemianpour@users.noreply.github.com>
Date: Mon, 24 Nov 2025 13:32:40 +0000
Subject: [PATCH 08/11] Implement basic wc command in Python

---
 implement-shell-tools/wc/wc.py | 22 ++++++++++++++++++++++
 1 file changed, 22 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 00000000..6d534920
--- /dev/null
+++ b/implement-shell-tools/wc/wc.py
@@ -0,0 +1,22 @@
+import argparse
+
+# Setup argument parser
+parser = argparse.ArgumentParser(
+    prog="wc",
+    description="Count lines, words, and characters"
+)
+parser.add_argument("paths", nargs='+', help="Files to count")
+
+args = parser.parse_args()
+
+for path in args.paths:
+    # Read the file
+    with open(path, "r") as f:
+        content = f.read()
+
+    # Count lines, words, characters
+    lines = len(content.rstrip('\n').split('\n'))
+    words = len(content.split())
+    chars = len(content)
+
+    print(f"{lines:8}{words:8}{chars:8} {path}")  
\ No newline at end of file

From df5b8e52d4de7c1ff58b14ccea03e1dd7754b7c1 Mon Sep 17 00:00:00 2001
From: zohrehKazemianpour
 <129424353+zohrehKazemianpour@users.noreply.github.com>
Date: Mon, 24 Nov 2025 13:36:30 +0000
Subject: [PATCH 09/11] Implement wc command with -l, -w, and -c flags

---
 implement-shell-tools/wc/wc.py | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/implement-shell-tools/wc/wc.py b/implement-shell-tools/wc/wc.py
index 6d534920..329e4512 100644
--- a/implement-shell-tools/wc/wc.py
+++ b/implement-shell-tools/wc/wc.py
@@ -6,6 +6,9 @@
     description="Count lines, words, and characters"
 )
 parser.add_argument("paths", nargs='+', help="Files to count")
+parser.add_argument("-l", "--lines", action="store_true", help="Count lines only")
+parser.add_argument("-w", "--words", action="store_true", help="Count words only")
+parser.add_argument("-c", "--chars", action="store_true", help="Count characters only")
 
 args = parser.parse_args()
 
@@ -19,4 +22,11 @@
     words = len(content.split())
     chars = len(content)
 
-    print(f"{lines:8}{words:8}{chars:8} {path}")  
\ No newline at end of file
+    if args.lines:
+        print(f"{lines:8} {path}")
+    elif args.words:
+        print(f"{words:8} {path}")
+    elif args.chars:
+        print(f"{chars:8} {path}")
+    else:
+        print(f"{lines:8}{words:8}{chars:8} {path}")  
\ No newline at end of file

From 36020221416b0290b903d3d22db2d41daffdf335 Mon Sep 17 00:00:00 2001
From: zohrehKazemianpour
 <129424353+zohrehKazemianpour@users.noreply.github.com>
Date: Mon, 24 Nov 2025 13:50:33 +0000
Subject: [PATCH 10/11] Add total line for multiple files in wc

---
 implement-shell-tools/wc/wc.py | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/implement-shell-tools/wc/wc.py b/implement-shell-tools/wc/wc.py
index 329e4512..f3e00f0a 100644
--- a/implement-shell-tools/wc/wc.py
+++ b/implement-shell-tools/wc/wc.py
@@ -12,6 +12,11 @@
 
 args = parser.parse_args()
 
+# Track totals
+total_lines = 0
+total_words = 0
+total_chars = 0
+
 for path in args.paths:
     # Read the file
     with open(path, "r") as f:
@@ -22,6 +27,11 @@
     words = len(content.split())
     chars = len(content)
 
+    # Add to totals
+    total_lines += lines
+    total_words += words
+    total_chars += chars
+
     if args.lines:
         print(f"{lines:8} {path}")
     elif args.words:
@@ -29,4 +39,17 @@
     elif args.chars:
         print(f"{chars:8} {path}")
     else:
-        print(f"{lines:8}{words:8}{chars:8} {path}")  
\ No newline at end of file
+        print(f"{lines:8}{words:8}{chars:8} {path}")  
+
+        
+# Print totals if multiple files
+if len(args.paths) > 1:
+    if args.lines:
+        print(f"{total_lines:8} total")
+    elif args.words:
+        print(f"{total_words:8} total")
+    elif args.chars:
+        print(f"{total_chars:8} total")
+    else:
+        print(f"{total_lines:8}{total_words:8}{total_chars:8} total")        
+

From 3b7cf4b780fa3ea0681359a85e89b167fbfa75a1 Mon Sep 17 00:00:00 2001
From: zohrehKazemianpour
 <129424353+zohrehKazemianpour@users.noreply.github.com>
Date: Sun, 8 Feb 2026 14:32:29 +0000
Subject: [PATCH 11/11] Address PR review: reduce duplication and fix flag
 handling

---
 implement-shell-tools/cat/cat.py | 51 +++++++++-------------
 implement-shell-tools/ls/ls.py   | 32 ++++++++------
 implement-shell-tools/wc/wc.py   | 73 +++++++++++++-------------------
 3 files changed, 68 insertions(+), 88 deletions(-)

diff --git a/implement-shell-tools/cat/cat.py b/implement-shell-tools/cat/cat.py
index 108678d9..7743c111 100644
--- a/implement-shell-tools/cat/cat.py
+++ b/implement-shell-tools/cat/cat.py
@@ -13,38 +13,25 @@
 
 args = parser.parse_args()
 
-line_number = 0  # Shared counter across all files
+line_number = 1  # Shared counter across all files
 
-# Process each file
-for path in args.paths:  # LEVEL 1: for loop starts
-    with open(path, "r") as f:  # LEVEL 2: inside for loop
-        content = f.read()  # LEVEL 3: inside with block
+for path in args.paths:
+    with open(path, "r") as f:
     
-    # Check if numbering is needed
-    if args.number:  # LEVEL 2: inside for loop
-        lines = content.split("\n")  # LEVEL 3: inside if
-        numbered_lines = []
-        
-        for index, line in enumerate(lines):  # LEVEL 3: inside if
-            line_number = line_number + 1  # LEVEL 4: inside inner for
-            numbered_line = f"{line_number:6}\t{line}"
-            numbered_lines.append(numbered_line)
-        
-        print("\n".join(numbered_lines))  # LEVEL 3: inside if
-    
-    elif args.number_nonblank:  # LEVEL 2: inside for loop
-        lines = content.split("\n")  # LEVEL 3: inside elif
-        numbered_lines = []
-        
-        for line in lines:  # LEVEL 3: inside elif
-            if line.strip() == "":  # LEVEL 4: inside inner for
-                numbered_lines.append(line)
+        lines = f.read().splitlines()
+
+    output = []
+    for line in lines:
+        if args.number_nonblank:
+            if line.strip():
+                output.append(f"{line_number:6}\t{line}")
+                line_number += 1
             else:
-                line_number = line_number + 1
-                numbered_line = f"{line_number:6}\t{line}"
-                numbered_lines.append(numbered_line)
-        
-        print("\n".join(numbered_lines))
-    
-    else:  # LEVEL 2: inside for loop
-        print(content)  # LEVEL 3: inside else
\ No newline at end of file
+                output.append(line)
+        elif args.number:
+            output.append(f"{line_number:6}\t{line}")
+            line_number += 1
+        else:
+            output.append(line)
+
+    print("\n".join(output))
diff --git a/implement-shell-tools/ls/ls.py b/implement-shell-tools/ls/ls.py
index c99aaea3..e1e301b2 100644
--- a/implement-shell-tools/ls/ls.py
+++ b/implement-shell-tools/ls/ls.py
@@ -1,24 +1,30 @@
 import os
 import argparse
 
-# Setup argument parser
-parser = argparse.ArgumentParser(
-    prog="ls",
-    description="Lists contents of a directory"
-)
+parser = argparse.ArgumentParser(prog="ls", description="Lists contents of a directory")
 
 parser.add_argument("-1", dest="one_column", action="store_true", help="List one file per line")
 parser.add_argument("-a", "--all", action="store_true", help="Include hidden files")
-parser.add_argument("path", nargs='?', default=".", help="Directory to list (default: current directory)")
+parser.add_argument("paths", nargs='*', default=["."], help="Directories to list")
 
 args = parser.parse_args()
 
-# List directory contents
-files = os.listdir(args.path)
+for path in args.paths:
+    if len(args.paths) > 1:
+        print(f"{path}:")
 
-# Filter out hidden files unless -a flag is used
-if not args.all:
-    files = [f for f in files if not f.startswith('.')]
+    try:
+        files = os.listdir(path)
+        if not args.all:
+            files = [f for f in files if not f.startswith('.')]
+        
+        files.sort()
 
-for file in files:
-    print(file)
\ No newline at end of file
+        sep = "\n" if args.one_column else "  "
+        print(sep.join(files))
+        
+        if len(args.paths) > 1:
+            print()
+            
+    except FileNotFoundError:
+        print(f"ls: cannot access '{path}': No such file or directory")
diff --git a/implement-shell-tools/wc/wc.py b/implement-shell-tools/wc/wc.py
index f3e00f0a..500ac55e 100644
--- a/implement-shell-tools/wc/wc.py
+++ b/implement-shell-tools/wc/wc.py
@@ -1,55 +1,42 @@
 import argparse
 
-# Setup argument parser
-parser = argparse.ArgumentParser(
-    prog="wc",
-    description="Count lines, words, and characters"
-)
+parser = argparse.ArgumentParser(prog="wc", description="Count lines, words, and characters")
 parser.add_argument("paths", nargs='+', help="Files to count")
-parser.add_argument("-l", "--lines", action="store_true", help="Count lines only")
-parser.add_argument("-w", "--words", action="store_true", help="Count words only")
-parser.add_argument("-c", "--chars", action="store_true", help="Count characters only")
+parser.add_argument("-l", "--lines", action="store_true")
+parser.add_argument("-w", "--words", action="store_true")
+parser.add_argument("-c", "--chars", action="store_true")
 
 args = parser.parse_args()
 
-# Track totals
-total_lines = 0
-total_words = 0
-total_chars = 0
+# If no flags are provided, the default behavior is to show all three
+show_all = not (args.lines or args.words or args.chars)
+
+total_stats = [0, 0, 0] # lines, words, chars
 
 for path in args.paths:
-    # Read the file
     with open(path, "r") as f:
         content = f.read()
 
-    # Count lines, words, characters
-    lines = len(content.rstrip('\n').split('\n'))
-    words = len(content.split())
-    chars = len(content)
-
-    # Add to totals
-    total_lines += lines
-    total_words += words
-    total_chars += chars
-
-    if args.lines:
-        print(f"{lines:8} {path}")
-    elif args.words:
-        print(f"{words:8} {path}")
-    elif args.chars:
-        print(f"{chars:8} {path}")
-    else:
-        print(f"{lines:8}{words:8}{chars:8} {path}")  
-
-        
-# Print totals if multiple files
-if len(args.paths) > 1:
-    if args.lines:
-        print(f"{total_lines:8} total")
-    elif args.words:
-        print(f"{total_words:8} total")
-    elif args.chars:
-        print(f"{total_chars:8} total")
-    else:
-        print(f"{total_lines:8}{total_words:8}{total_chars:8} total")        
+    stats = [
+        len(content.splitlines()), 
+        len(content.split()), 
+        len(content)
+    ]
+    
+    for i in range(3):
+        total_stats[i] += stats[i]
+
+    output = []
+    if args.lines or show_all: output.append(f"{stats[0]:8}")
+    if args.words or show_all: output.append(f"{stats[1]:8}")
+    if args.chars or show_all: output.append(f"{stats[2]:8}")
+    
+    print(f"{''.join(output)} {path}")
 
+if len(args.paths) > 1:
+    total_output = []
+    if args.lines or show_all: total_output.append(f"{total_stats[0]:8}")
+    if args.words or show_all: total_output.append(f"{total_stats[1]:8}")
+    if args.chars or show_all: total_output.append(f"{total_stats[2]:8}")
+    
+    print(f"{''.join(total_output)} total")
\ No newline at end of file