Can linux cat command be used for writing text to file?

Question

That's what echo does:

echo "Some text here." > myfile.txt

Sounds like you're looking for a Here document

cat > outfile.txt <<EOF
>some text
>to save
>EOF

Here's another way -

cat > outfile.txt
>Enter text
>to save press ctrl-d

For text file:

cat > output.txt <<EOF
some text
some lines
EOF

For PHP file:

cat > test.php <<PHP
<?php
echo "Test";
echo \$var;
?>
PHP

I use the following code to write raw text to files, to update my CPU-settings. Hope this helps out! Script:

#!/bin/sh

cat > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor <<EOF
performance
EOF

cat > /sys/devices/system/cpu/cpu1/cpufreq/scaling_governor <<EOF
performance
EOF

This writes the text "performance" to the two files mentioned in the script above. This example overwrite old data in files.

This code is saved as a file (cpu_update.sh) and to make it executable run:

chmod +x cpu_update.sh

After that, you can run the script with:

./cpu_update.sh

IF you do not want to overwrite the old data in the file, switch out

cat > /sys/devices/system/cpu/cpu1/cpufreq/scaling_governor <<EOF

with

cat >> /sys/devices/system/cpu/cpu1/cpufreq/scaling_governor <<EOF

This will append your text to the end of the file without removing what other data already is in the file.

cat > filename.txt

enter the text until EOF for save the text use : ctrl+d

if you want to read that .txt file use

cat filename.txt

and one thing .txt is not mandatory, its for your reference.