Introduction
The tutorial is about how to use cat,sed and awk commands to display file contents . when we start with linux basic commands, we generally introduced with cat command to show file contents. But with the help of sed and awk command also, you can see the file contents. The output will be similar to cat command.
How to show file contents on Linux/Unix systems
With the help of 3 commands cat, sed and awk we can read or show the file contents.
(1) Cat command
cat command is used for concatenating files and print on the standard output .
Use the below given syntax to display file contents –
cat /path/of/file
Example:
(2) Sed Command
For stream editor for filtering and transforming text we use sed command. The command is very powerful. Knowledge of regex is must for using sed command.
Use the below given syntax to display file contents –
sed '' /path/of/file
Example:
Awk command
awk is a pattern scanning and text processing language.
Use the below given syntax to display file contents –
awk '{print $0}' /path/of/file
Example:
We hope these commands will be helpful for you. We can use these commands in scripting as well.
Hi sharad,
I am planning to verify data content and extension of a file matches. but for excel sheet, I need to check whether “CMD” command is there inside the file without using grep condition. Please find the below piece of code:
filename=$1
file_ext=`echo $filename | cut -d “.” -f2`
if [ $file_ext == “xlsx” ]; then
temp_ext=” Microsoft Excel 2007+”
elif [ $file_ext == “docx” ]; then
temp_ext=” Microsoft Word 2007+”
elif [ $file_ext == “pdf” ]; then
temp_ext=” PDF document”
elif [ $file_ext == “doc” ]; then
temp_ext=” document”
elif [ $file_ext == “xls” ]; then
temp_ext=” CDF V2 Document”
fi
result=$(file $filename|cut -d “,” -f1)
if [[ $result == $temp_ext ]]; then
echo “Valid file format, Extension and Data content is $temp_ext and $result”
else
echo “Not a valid file format!! Extension and Data content is $temp_ext and $result”
fi
Here before the last else statement, need to check whether the cmd command is therein the file without using grep. please help me with this.