How do I echo output from shellscript?

[paulh177]

I have a noddy shellscript which does some untars and runs a few makes.
I cannot for the life of me remember how to echo output from commands in a shellscript to stdout or capture output to a logfile

can someone point me in the right direction please?

fragment example (there's maybe 50 lines of this sort of stuff) :

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gunzip -c libpng-*.tar.gz |tar xf -
rm libpng-*.tar.gz
mv libpng-* libpng
cd libpng
make -f scripts/makefile.std CC=gcc ZLIBLIB=../zlib ZLIBINC=../zlib
rm *.so.* *.so
cd ..

[rarsa]

There are two things here.

Normally running that script will send the output to the stdout, no need to do anything else.

If you want to send ALL the output from the script to a log file the best way is to execute the script redirecting output to a log file with ">"

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# myscript > mylog.log

If you just want to selectivelly send the output of some commands and append them to a new or existing log file use ">>" in each of the commands

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LOG_FILE=/tmp/mylog.log
echo "#first line of my log file" > ${LOG_FILE}
gunzip -c libpng-*.tar.gz |tar xf - >> ${LOG_FILE}
rm libpng-*.tar.gz 
mv libpng-* libpng 
cd libpng 
make -f scripts/makefile.std CC=gcc ZLIBLIB=../zlib ZLIBINC=../zlib 
rm *.so.* *.so 
cd ..

[Pizzasgood]

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echo "Hola mundo"
MyVariable=`which geany`
echo $MyVariable
echo "This will output contents of $MyVariable also, along with text"
echo 'You need single quotes to do an exclamation!"
echo 'They also let you do the $ sign without being interpreted'
echo `which geany`
echo "This goes into afile.txt" > afile.txt
echo "This gets appended to afile.txt" >> afile.txt
which geany > anotherfile.txt

Note: > makes a new file or replaces an existing one. >> makes a new file or appends to an existing one.

You can redirect the stderr to the output or /dev/null also

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rm NONexistantFile 2>&1
rm NONexistantFile 2>/dev/null

[paulh177]

OK thanks guys.
it's the 2>&1 that I was particularly trying to remember ...
if i have

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# command_string 2>&1 >> logfile

then that would ensure both stderr and stdout from command_string are captured to a file?

[Pizzasgood]

It should. I had problems with a particular command skipping out of something similar once though, but I was probably doing something different (I think it was when I was storing it in a variable to log later).