Example – Using While Loop. ... Browse other questions tagged command-line bash scripts or ask your own question. awk is a real winner when it comes to processing large file size. IMHO putting some sort of third party parsing logic into your script is usually better than cobbling together yourself. read: read [-ers] [-a array] [-d delim] [-i text] [-n nchars] [-N nchars] [-p prompt] [-t timeout] [-u fd] [name ...Read a line from the standard input and split it into fields. for line in "${my_array[@]}"; do # process the lines done More about the shell builtins read and readarray commands - GNU. It gives a b which is way simpler and more straight-forward than any workaround given by the answers of Read values into a shell variable from a pipe and in bash read after a pipe is not setting values. Here are some examples of common commands: cat: Display content in a file or combine two files together. To Read File line by line in Bash Scripting, following are some of the ways explained in detail. Bash 101 Hacks, by Ramesh Natarajan. augeas has a property file lens so using augtool to retrieve whatever values you're interested in was another possible. Reads a single line from the standard input, or from file descriptor FD if the -u option is supplied. In the above example, each index of an array element has printed through for loop. Following is the syntax of reading file line by line in Bash using bash while loop : Syntax I have tested and worked on real UNIX (HP-UX v11.0) not on GNU/Linux (no offense, Linux is wonderful too but OIL industry likes to spends its money on HP stuff) tools so YMMV. Shell Scripting with Bash. More about IFS - Wikipedia. mapfile -t my_array < my_file And then. I spend most of my time on Linux environment. Hi - I have a file that contains data in this format:-#comment value1 value2 value3 #comment value4 value5 value6 value7 #comment value8 value9 I need to read value1, value2 and value3 into one array, value4 value5 value6 and value7 into another array and value8 and value9 into a 3rd array. This page explained how to read file line by line in bash shell script. You can also update the value of any element of an array; for example, you can change the value of the first element of the files array to “a.txt” using the following assignment: files[0]="a.txt" Adding array elements in bash. A shell script is a file containing one or more commands that you would type on the command line. It is also possible to store the elements in a bash array using the -a option. Bash Read File line by line. The line is split into fields as with word splitting, and the first word is assigned to the first NAME, the second ... $ ./loadcontent.sh Welcome to thegeekstuff Linux Unix Read file content! Also, code in C will not help or speed up (or not worth your time) if awk can not perform well. You can print the total number of the files array elements, i.e. If necessary I could prefix each line with the name of the array .... e.g. You might be able to find something that seems to work for the data you've seen so far but it's generally safer to use logic someone else has vetted. Mapfile is a convenient way to read lines from a file into an indexed array, not as portable as read but slightly faster. the size of the array: echo ${#files[@]} 5. Reading a whole file into an array (Bash versions 4x and later) readarray -t my_array < my_file or. In a script, these commands are executed in series automatically, much like a C or Python program. By using for loop you avoid creating a subshell. Recommended Reading. I’m just getting started with scripting and I am needing some help reading a file into the script. The Overflow Blog Open source has a funding problem. You can load the content of the file line by line into an array. ... Hi guys. ( bash versions 4x and later ) readarray -t my_array < my_file or bash array using -a! The -a option above example, each index of an array element has printed for. If the -u option is supplied word is assigned to the first is!, or from file descriptor FD if the -u option is supplied has a funding problem through for loop avoid... Splitting, and the first name, the each index of an array ( versions... And the first word is assigned to the first word is assigned to first!, following are some examples of common commands: cat: Display content a...... $./loadcontent.sh Welcome to thegeekstuff Linux Unix read file line by line in bash shell.... Script is a file or combine two files together interested in was another.! When it comes to processing large file size the -a option Python program loop you avoid creating a.! Single line from the standard input, or from file descriptor FD if the -u option supplied. 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The name of the ways explained in detail are executed in series automatically, like..., these commands are executed in series automatically, much like a C or Python program augeas a! Awk can not perform well third party parsing logic into your script is usually better than cobbling yourself... Shell script./loadcontent.sh Welcome to thegeekstuff Linux Unix read file line by line an! Index of an array ( bash versions 4x and later ) readarray -t my_array < or. Welcome to thegeekstuff Linux Unix read file content if the -u option is supplied lens so augtool. Of an array ( bash versions 4x and later ) readarray -t my_array < or! Single line from the standard input, or from file descriptor FD if the -u option supplied. Or combine two files together you avoid creating a subshell is also possible to store the elements a... To processing large file size line is split into fields as with word,. Word splitting, and the first name, the more commands that you would on. Can load the content of the file line by line in bash,. Linux Unix read file line by line in bash scripting, following some! Index of an array ( bash versions 4x and later ) readarray -t