Linux & the Command Line

In this page

  1. Disk utilities
  2. Software management
  3. Arguments in the command line
  4. File manipulation
  5. SHA generation
  6. bash

1. Disk utilities

Some commands to get information on disk parameters, usage, and what not. 

$ sudo hdparm -i /dev/sda      # Find hd parameters
$ df -h                        # Disk usage

2. Software management

Some options for the apt series and related commands. 

$ sudo apt-get update                    # Updates the list of applications
$ sudo apt-get dist-upgrade              # Do the real app update
$ dpkg --get-selections                  # Find installed programs
$ sudo apt-get purge indicator-messages  # Uninstall plugin for panel pigdin icon

3. Arguments in the command line

Two options to use a file content as command line arguments: 

$ <command> $(cat <argument_file>)      # sudo apt-get install $(cat args.txt)
$ cat <argument_file> | xargs <command> # cat args.txt | xargs sudo apt-get install

4. File manipulation

File Encoding

Convert the file encoding, in particular when it is not compatible with some programs that use utf-8: 

$ file -bi <filename>                                            # Find encoding
$ iconv -f <enc> -t <new_enc (ex: utf-8)> <file> > <new_file>    # Change encoding

File renaming

Renames, recursively, all files in <rootdir>, and below, so that they only contain lowercase characters. This is taken from this page) and it is not garanteed to work with special characters. 

$ find <rootdir> -depth -exec rename 's/(.*)\/([^\/]*)/$1\/\L$2/' {} \;

5. SHA generation

Generate sha-1 and sha-256 hashes (note the -n option to avoid including a new line character in the generation of the hash): 

$ echo -n "test" | sha1sum | awk '{print $1}'    # sha-11
$ echo -n "test" | sha256sum | awk '{print $1}'  # sha-256

6. bash

Useful bash commands: 

$ bash         # Re-initializes the bash shell