System-Programming

A collection of various C programs utilising system calls, signals, pipes, threads and BASH

move_copy

• Moves or copies a source directory into destination directory
• Maintains the original files structure in destination folder
• Can work on a subset of file extensions like copy only pdf txt mp4 files
• Usage: ./cpmvdir source_dir destination_dir option [extension_list]
  • source_dir: directory to copy/move
  • destination_dir: directory where files will be copied/moved
  • option: intent(-cp/-mv)
  • extension_list: list of file extensions to copy/move

process_search

• Searches for processes in a root process tree structure
• Based on the option provied, crawls through the process tree and prints required information
• Usage: ./prcsearch root_process process_id1 [process_id(n)] [option]
  • root_process: process who's process tree has to be searched
  • process_id1, process_id(n): processes to process based on option
  • option:
    • dn: lists the PIDs of all the non-direct descendants of process_id1 (only)
    • id: lists the PIDs of all the immediate descendants of process_id1
    • lp: additionally lists the PIDs of all the sibling processes of process_id1
    • sz: Lists the PIDs of all sibling processes of process_id1 that are defunct
    • gp: lists the PIDs of all the grandchildren of process_id1
    • zz: additionally prints the status of process_id1 (Defunct/ Not Defunct)
    • zc: lists the PIDs of all the direct descendants of process_id1 that are currently in the defunct state
    • zx: lists the PIDs of the direct descendants of process_id1..process_id[n] that are currently in the defunct state

my_bash

• Simulate BASH operations like piping, conditional execution, sequential execution and background processing
• Usage: ./my_bash

automated_backups

• BASH script to generate backups of pdf and txt files, runs infinitely
• The backup process has 2 phases:
  • Complete: Create tar of all pdf and text files
  • Incremental: Create tar of only those pdf and text files modified since previous backup
• TAR files are stored in $HOME/backup/cb (for complete backup) or $HOME/backup/ib (for incremental backup)
• Usage: ./createbackups.sh

pipe_cmds_c

• Simulate cat sample.txt | grep word | wc -w BASH command in C
• Makes use of execlp(), pipe(), fork() and dup2()
• Usage: ./pipecmd